Functions of proteins

› Functions of proteins

Proteins are very important macromolecules with essential functions in the body.
Proteins make up to 50% of the dry body weight and have specific functions. All the activities like structural support, growth, respiration, digestion, energy production, osmoregulation are brought about by proteins. The chemical structures and chemical compositions regulate the roles of proteins.

Proteins in structural support

The structural proteins form the basic matrix of structural supports and protective covers.
Keratin, elastin and collagen are a few examples these types, carrying out the supportive and protective role.
Keratins (α and β) are the primary constituent of growths and structures of skin like hair (also wool), nails (also claws and hoofs), horns and beaks.
Elastin is very important for pressure wave propagation functions in arterial walls, especially in large elastic blood vessels like aorta.
Elastin contributes to the elasticity of skin, lung, bladder and elastic cartilage.
Collagen is fibrous, mostly found outside the cells and forms the extracellular matrix giving structure to the animal body.
It is the main component of the matrix of bone, cartilage, tendons, ligaments, fascia and skin.

Functions of proteins in movement and contraction

All our body movements are brought about by movement of muscles.
Muscles are categorized as skeletal muscle (bringing about skeletal movement, locomotion and maintenance of posture), smooth muscle (bring about involuntary movements like, movement of intestine, urinary bladder, stomach, esophagus, intestines, blood vessels) and cardiac muscle (for beating of the heart).
All these muscles are mainly made of muscle cells.
Muscle cells contain myofibrils which are organised into sub-units called sarcomeres.
The filaments of myofibrils are constructed from contractile proteins.
Thin type of myofibrils consists mainly of actin and the thick type of myofibril consists mainly myosin.

Proteins in control of growth differentiation

There are proteins having a regulatory role like growth differentiation.
Growth differentiation factors (GDF) are named GDF1 to GDF15.
These factors regulate complex processes in ovulation, embryonic development, muscle development (GDF8-myostatin) and inflammatory and apoptotic pathways (GDF15) during diseases and injuries.

Functions of proteins in gene expression

The messages and codes in the genes are not totally expressed at the same time.
They are switched on and off in respect to the phase of growth, organ under concern and biological timetable.
In expression of DNA and cell differentiation repressorproteins bind to specific DNA segments and prevent the formation of the particular product of that segment.
These DNA-binding proteins are coded by regulator genes.
The segment bound by repressor is called operator.
By binding to operator, the repressor prevents the creation of messenger RNA by the RNA polymerase.

Functions of proteins in tissue repair and maintenance

Continuous supply of amino acids and building of proteins is necessary for the tissue growth, repair and maintenance.
Constantly new tissues of hair, skin, nails and teeth are added to our body to replace the dead cells which have sloughed off.
Epidermis and blood cells have a life of about one month and are to be constantly replaced.
The cell in the gastro-intestinal system lining last only for 2 weeks.
There is an elaborate process of tissue regeneration all over the body with their use.
In special circumstances like injury and damage, increased activity of cell formation is induced and new tissue is formed.

Functions of proteins as hormones

These are messengers helping in regulating certain body chemical activities.
Many categories of hormones are secreted by endocrine glands like thyroid gland, pancreas, adrenal gland, ovary, testis and thymus gland for carying out many vital biological actities.
Complex hormones like melatonin and seratonin affect the sleep and mood whereas thyroid hormones affect the basal metabolic rate and synthesis of proteins.
Insulin regulates glucose utilisation whereas a myriad hormones regulate reproduction.

Functions of proteins as enzymes and catalysts

Proteins as enzymes and catalysts facilitate chemical reactions in the body.
Enzymes are large structures having essential kinetic functions in bringing about all biochemical reactions.
The functions of the gastrointestinal system are facilitated by different enzymes secreted for digestion of proteins, fats and carbohydrates.

Functions of proteins as antibodies and immune protection

Antibodies are proteins and are responsible for binding to specific foreign bodies and make them harmless, ineffective and eliminate them.
There are two types of main functions for immunoproteins made and used by the body, namely innate immune system and adaptive immune system.
In innate immune system the innate response is triggered by pattern recognition receptors (proteins) which identify pathogen-associated molecular patterns (PAMPs), which are associated with cellular stress or microbial pathogens. Cytokines (like interleukins, chemokines, interferons) which are glycoproteins are released to combat the antigen in various ways.

The Interleukins (secreted proteins /signaling molecules) create communication between white blood cells (leukocytes). Chemokines (chemotactic cytokines) are secreted by cells.
Their functions are to promote chemotaxis (chemically induced movement) of the nearby responsive cells towards the site of antigen.

Interferons (IFNS) have many antiviral activities like shutting down the synthesis of proteins in the host cells. In the functions of innate immune system, a complement system containing over 20 different proteins starts a biochemical cascade of attacking the surfaces of foreign cells.
This complements the functions of antibodies in killing the pathogens. In the innate immune system, white blood cells (leukocytes) like 'natural killer cells' which are cytotoxic lymphocytes kill the tumors and virus infected cells by releasing small cytoplasmic granules called perforin (cytolytic proteins) and granzyme (serine proteases) causing the target cell to die by apoptosis (programmed cell death).

Adaptive immune system has stronger immune response as well as immunological memory.
Each pathogen is remembered by signature antigen protein.
The responses are generated tailor made to specific antigen.
When a pathogen infects more than once the memory cells are quickly used to eliminate it.
Lymphocyte B cells and T cells carry receptor molecules which can recognize particular target antigen. Cytotoxins such as perforin are released into the target cell inducing it to undergo apoptosis.

Functions of proteins in Fluid and electrolyte balance and osmoregulation

Globulins and albumins are the important blood proteins molecules doing the functions of maintaining the fluid and electrolyte balance between the cells and the extracellular space.
The proteins present in the capillary beds (blood vessels of one-cell thickness) pull the blood fluid from the tissues into the capillary beds.
This osmotic pressure exerted by proteins is called colloid osmotic pressure or oncotic pressure.
These functions protects the body from fluid retention and edema.
If the blood plasma levels of proteins are reduced due to proteinuria (loss through urine) or as a result of malnutrition, oncotic pressure is reduced and fluid retention occurs leading to many health complications.
Proteins are abundant in biological membranes.
Cellular membranes form channels and pumps regulating fluids and ions inside and outside the cells.
Many cellular channels allow ions to move from higher concentration to lower concentration.
However for forcing ions from lower concentration to higher concentration (pumps-active transport) energy in the form of adenosine triphosphate (ATP) are required.
Proteins being amphoteric, perform the functions of buffering and maintaining the optimum blood pH.

Functions of proteins in transport and storage

One of the important functions of Proteins is the transport of essential molecules from one part of the body to other.
Functions of hemoglobin and myoglobin are primarily in transport of oxygen to the tissues.
Transferrin is transporter of iron and helps in the storage of iron in the liver.
Cytochrome C functions as electron transport and albumin transports fatty acids in the bloodstream.
Ovalbumin are storage proteins found in the egg white providing nutrition to the embryo.

Functions of proteins in metabolism and energy production

Though proteins are not primary source of energy, in the event of shortage of body fuels like carbohydrates and fats, they are utilized in energy production functions.
They provide the nitrogenous base adenine for ATP and also creatine phosphate in the cell metabolism functions.
Some amino acids by the process called gluconeogenesis are degraded to pyruvate and glucose for production of energy.
Some of the amino acids are reduced to ketone bodies (acetoacetate) which can be metabolised for energy by muscle and brain when blood glucose levels are low.

Functions of proteins as receptors and neurotransmitters

Many proteins do the functions of signal detection and its conversion into another type of signal.
The functions of proteins Rhodopsin in light detection and conversion of the photo-signals into neurosignals is well known.
Proteins play many important functions in generation as well as transmission of nerve impulses.
Many monoamines like dopamine, epinephrine, norepinephrine, serotonin, histamine, melatonin have neurotransmitters functions.
Many neuropeptides have been discovered and 'neuropeptide Y' is one of them having wide range of neurological functions in food intake, obesity and anorexia nervosa.
Acetylcholine receptor (AChR-an integral membrane) is one of the neuroreceptor proteins.
It is embedded in the 'postsynaptic density (PSD)' region at the membrane of postsynaptic neuron. These proteins function as neurotransmitter receptor.
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Vitamin C and liver - detoxification of body

› › Vitamin C and liver detoxification

Vitamin C is an important support in liver detoxification mechanism.

Role of vitamin C in liver detoxification

Vitamin C helps in the detoxification and removal of the harmful substances from the body. Liver as the main blood purifying organ of the body removes the harmful substances from the blood. Most of these toxic substances are absorbed into the body through gastrointestinal system, lungs and skin. Many toxic chemicals are also produced as by-products of biological processes.

If these toxic substances are not removed from the blood due some disease or due lack of antioxidants, especially vitamin C, the toxins may accumulate in very important parts of the body like brain and kidney leading to devastating health problems. Depletion or lack of vitamin C impairs the blood purifying mechanism of the liver.

Detoxification takes place in two phases. In phase 1, the toxins are reduced to smaller less harmful fragments. This is achieved by the biological processes like hydrolysis, reduction and oxidation. During this phase 1 detoxification free radicals are formed and in excess they can destroy the cells.

The availability of ascorbic acid and other oxidants at this stage neutralizes the free radicals and protects the cells from the oxidative damages in this phase. In phase 2 of detoxification, the fragmented molecules are bound to sulphate, glycine and glutathione to create new non toxic substance and excreted in bile or urine.

Role of vitamin C in treatment of hepatitis

Ascorbic acid along with hepatic stimulants like alpha lipoic acid and milk thistle have been used successfully in the treatment of viral and chronic hepatitis. Vitamin C (sodium ascorbate) given via intravenous route will help liver detoxification bringing relief in a few days. Affected with hepatitis, the mitochondria may get damaged and free radical scavenging may get upset. This results in excessive free radicals and the resultant destruction of the cells. The presence of vitamin C mops up the free radicals and the conditions improve.

Role of vitamin C in treatment of NFLD (Nonalcoholic Fatty Liver Disease)

Steatosis (also called adipose degeneration, fatty degeneration or fatty change) is a process wherein lipids are abnormally retained inside the cells. Steatosis of these cells causes NAFLD.
liver steatosis
Cells with NFLD showing nuclei pushed to the sides by the lipids (enlarge)
It is believed that NFLD is associated with the free radical damage and oxidative stress. Experiments in 'choline deficiency' induced NFLD have shown that vitamin C blocks and prevents NFLD.
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Causes of Pellagra disease (niacin deficiency)

› › Causes of pellagra disease

Causes of pellagra disease are or malabsorption of niacin (vitamin B3), and/or tryptophan (an essential amino acid). Depending on the formative factors pellagra may be primary or secondary.

Primary pellagra

Primary pellagra is the acute nutritional deficiency of niacin and/or tryptophan in the diet in freely available form.
Vitamin B3 (niacin, nicotinamide or nicotinic acid) deficiency causes pellagra disease

The deficit of vitamin B3 deranges all cellular functions and all biochemical mechanisms of the body systems go haywire and leads to the resultant debilitating symptoms. These causes of the disease are primary. Poor people are generally under nourished and their food may not include vitamin B3 and protein rich foods like organ meat, poultry, egg, milk, yeast etc..

This borderline deficiency leads to pellagra in them when there is a slight slide in their health. Populations, who depend mainly on maize as staple food tend to develop pellagra.
Maize food has niacin in biologically unavailable forms and causes pellagra disease.

Earlier populations boiled maize with lime before eating and it is found that this process makes niacin biologically available. People in low income groups, prisoners, people affected by famine and refugees are in the risk group. These people are to be monitored for symptoms of deficit and are to be helped with supplementation of vitamins.

Tryptophan (an essential amino acid) deficiency causes pellagra

Human body can produce vitamin B3 from the amino acid tryptophan.
Tryptophan is one of the amino acids which human body cannot synthesize and hence it is called as an essential amino acid. It has to be sourced only from food. The deficiency of tryptophan in diet causes pellagra disease.

Food of animal sources has sufficient levels of tryptophan.
In the food of plant origin tryptophan is available in nuts especially groundnuts and also in various beans.
Vegan food habit causes this malady. Vegans who do not include beans and nuts in their food are in the risk group.

Secondary pellagra disease causes
In a number of situations vitamin B3 may be present in available form and in sufficient quantities in the food. However extraneous factors lead to pellagra.
The presence of other diseases, assimilation disorders, utilization disorders and altered biosynthesis processes in the body may give rise to pellagra symptoms.

Leucine (an essential amino acid) can precipitate pellagra if present in high concentrations in the diet
People who frequently eat millet (sorghum or jowar) and whose staple food is millet are found to be affected by pellagra disease.
Millet contains both niacin and tryptophan. The causes of pellagra in millet eating populations are found to be the excessive leucine availability in millet and its interference in tryptophan metabolism and in the subsequent synthesis of niacin.

Chronic diarrhea causes pellagra

Chronic diarrhea, if not diagnosed and treated may lead to pellagra. As the individual's digestion and absorption mechanism gets affected in chronic diarrhea nutritional deficiency and dehydration sets in. This is not only the precipitating factor for pellagra but also many deficiency complications.

Elderly people are prone to develop pellagra
Elderly people's digestive system slowly gets impaired and the digestion and assimilation process slows down. Their condition is to be monitored closely and niacin and other vitamin supplements are to given. They are in the risk group of developing vitamin B3 deficiency.

Impaired digestion and gastrointestinal disorders causes pellagra

Persons with impaired digestive systems, celiac disease and tropical sprue develop nutritional deficiencies.They are prone to get deficit of vitamin B3.

Chronic alcoholism causes pellagra disease
Alcoholics due to their careless and erratic food habits, may not eat . The absorption and utilization of the niacin also gets affected in the alcoholics and they are prone to develop vitamin B3 deficiency.

Anorexia nervosa and pellagra
Anorexia nervosa, is a mental illness in which the patient suffers from low body weight. He evaluates himself to be overweight and starves himself with an obsessive fear of putting on weight.

In this mental disorder apart from starving, the patient may also exercise excessively and follow weight control measures. This naturally leads to nicotinic acid deficiency. Vit. B3 deficit leads to production of hunger suppressing endorphins and lack of appetite. The patient may develop skin and early psychiatric symptoms.

Carcinoid syndrome and pellagra

Carcinoid tumors are malignant tumors occurring on the intestinal wall and lungs. In these patients tryptophan is excessively converted into serotonin. This altered protein metabolism results in negligible niacin synthesis and causes this disease.

Hartup disease and pellagra
Hartups disease is a genetic autosomal disease caused by recessive trait. This impairs absorption of tryptophan in the intestines as well as kidneys. Very little amounts of tryptophan is absorbed in the intestines and excess of tryptophan is lost in the excretion. With this, there is no conversion of tryptophan into niacin and hence its deficiency disease.

Certain drugs and medications causes pellagra
The production of niacin from tryptophan depends on a co enzyme which is derived from vitamin B6. Isoniazid (used in the treatment of tuberculosis) and 3-mercaptopurine (used in the treatment of leukemia interfere with the metabolism of vitamin B6 and causes nicotinamide deficit. Some medications like chloramphenicol, hydantoins, phenobarbital, pyrazinamide and 5-fluorouracil have been found to become causes of nicotinamide deficiency disease.

Certain diseases and health conditions causes nicotinamide deficiency

Patients with liver cirrhosis, chronic ulcerative colitis, prolonged febrile illness, diabetes mellitus, AIDS, patients on intravenous fluids and patients on maintenance haemodialysis are prone to develop it. Liver cirrhosis, if untreated causes pellagra.
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pellagra disease (niacin deficiency) - diagnosis, treatment and prevention

› › Diagnosis, treatment and prevention of pellagra disease

Diagnosis of pellagra disease (niacin deficiency) is very difficult, whereas its treatment and prevention are simple.

Diagnosis of pellagra

For diagnosis of pellagra, earlier we had to rely on the symptoms narrated by the patient, signs observed and the nutritional deficiency status and diet of the patient.
In the early stages fewer of the niacin deficiency signs may be present and it becomes very difficult for the diagnosis of pellagra.
It will be easier for diagnosis and confirmation of the presence of pellagra disease, if all the three "D" symptoms (dermatitis, diarrhea and dementia) are present.
Nowadays the diagnosis can be confirmed by the measurement of excretion of N-methylnicotinamide per day in urine and treatment can be started.
However the facilities may not be easily available for the analysis and diagnosis in the developing and underdeveloped countries to start pellagra treatment with niacin supplements to remove deficiency.
If the patient has some of the signs and symptoms of pellagra the following steps may help in treatment and prevention.
The first step in diagnosis, treatment and prevention is to find out whether the patient is coming from pellagra prevalent region with niacin deficiency.
Next step in diagnosis and prevention is to ascertain the patient's food habits and find out whether maize is his staple food.
Persons afflicted by pellagra disease generally appear weak, underweight and poorly nourished.
It has to be ascertained whether the patient has dermatitis, diarrhea or dementia and nervous impairment.
Therapeutic doses of nicotinamide may be given for a few days to investigate for improvement in the condition.
If the disease is pellagra there will be marked improvement and the diagnosis of the disease is complete and treatment can be started.
Low serum levels of niacin and tryptophan may also confirm the disease and treatment can be started.
Low levels of pyridone and N-methylnicotinamide in urine can be due to niacin deficiency confirming the diagnosis for pellagra.
If less than 1.5mg of these organic compounds are excreted in a day, diagnosis of severe niacin deficiency is confirmed and immediate treatment is required.
The presence of three "Ds" (dermatitis, diarrhea and dementia) confirms the diagnosis of pellagra disease.
Dermatitis in pellagra patients has a characteristic appearance.
The exposed regions of the skin to sunlight get inflamed and red in appearance initially with marked margin with the unexposed skin.
This is a clear cut diagnosis of pellagra.
The swelling of tongue and mouth and oral sores also help in the diagnosis.
The chronic diarrhea and bleeding from intestine also help in diagnosis and treatment.
Symptoms like diminished sensitivity to touch, irritability, and tremor help in diagnosis.

Treatment for pellagra disease

If the patient is fairly in the advanced stage of pellagra, hospitalisation is required for of acute niacin deficiency.
Patient with milder symptoms may undergo treatment at home for niacin deficiency.
Patients with dementia are preferably given treatment at hospital for prevention of complications with niacin deficiency.
Oral administration of nicotinamide or nicotinic acid helps in the reversal of symptoms of niacin deficiency.
The exact dosage will be recommended by physician considering the stage of the disease and the age and weight of the patients.
Persons who are comatose, uncooperative or with severe swelling and blocking of the mouth may be given injections of vitamin B3 to resolve niacin deficiency.
For patients with dementia and severe pain tranquilizers may be given.
Anti-inflammatory antibiotic creams must be applied to skin conditions till the niacin deficiency resolves.
During treatment, prevention to exposure to sunlight is very important.
There can be dramatic change and healing after a few days of treatment for niacin deficiency.
With the treatment dermatitis slowly disappears, the gastrointestinal inflammation goes and the patient will be able to eat.
The neurological disorders slowly disappear and the patient becomes normal.
As the pellagra afflicted person will be malnourished, he should be given easily digestible protein rich, well followed by multivitamin supplement.
Though the primary pellagra responds well to treatment the secondary pellagra disease is harder because of the causes for its occurrence.

Prevention of pellagra disease

In the maize eating population relying on maize only as staple food has to be discouraged and addition of other cereals has to be encouraged for prevention of pellagra disease, affecting populations as a whole.
An inducement and requirement to fortify milled maize flour with niacin must be emphasised and regulated for prevention of pellagra.
For the prevention of nutritional deficiency caused diseases, it is very important to have diversity in the food consumed.
Food from animal sources like milk, egg, meat and fish is rich in vitamin B complex and tryptophan and this resource is to be included in daily consumption for prevention of deficiency.
Niacin rich plant food like nuts especially groundnuts must be included in diet for prevention deficiency and pellagra.
Prisoners, refugees and famine affected may not have and protein rich food and they are to be given nicotinamide supplements for prevention of pellagra disease.
Education on nutrition must be emphasised to spread awareness among people for prevention of Pellagra disease.
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Dr Joseph Goldberger - pellagra research contribution

Home > Dr Joseph Goldberger

One of the greatest research findings for the cause of the neglected humanity was by Dr Joseph Goldberger.

Dr Joseph Goldberger was born in Giralt, Hungary on July 16, 1874. He migrated along with his parents to United States in 1883 and settled in New York City. He earned his MD Degree in 1895 from the Bellevue Hospital Medical College (New York University School of Medicine).
Dr Joseph Goldberger after a stint of private practice at Wilkes-Barre, Pennsylvania, joined United States Marine Hospital Service (later PHS) as an Assistant Surgeon.
His first place of appointment was at the Port of New York and was assigned for the health inspection of immigrants.
Epidemiological skills of Dr Joseph Goldberger were sharpened when he worked on the control of yellow fever, dengue fever and typhus during 1902 - 1906.
In the year 1906 he married Marry against the wishes of the families.
During his studies on epidemics, Dr Joseph Goldberger contracted the diseases he studied like typhus and dengue fever.
In 1909 he published his research findings on Schamberg's disease connecting its origin to acarine mite.
Dr Joseph Goldberger was asked in 1914 to investigate on pellagra disease.
Working on the project he found that the inmates of prisons, orphanages and mental asylums were developing the ailment while the employees are not getting affected.
Dr Joseph Goldberger was sure that pellagra disease is not contagious and no germ is involved with it.
He also fed the affected children of orphanages and asylums with fresh food, meat and fresh vegetables.
There was dramatic recovery in their condition. Those of them who did not have the disease did not develop the disease.
Further he experimented with health volunteer prisoners and fed them only corn based food. Many of them developed pellagra rashes in about five months.
Joseph Goldberger
Dr Joseph Goldberger
Dr Joseph Goldberger to prove his point and to silence his detractors, injected blood of pellagra affected into his body and also on his assistant.
He also took swabs of nasal and throat secretions of the patients and rubbed onto his nose and throat.
Dr Joseph Goldberger collected scabs of pellagra disease rashes and swallowed them.
He did not contract the pellagra disease. Even after these demonstrations a section of the scientific community did not accept his theory that pellagra disease is due to nutritional deficiency.
Dr Joseph Goldberger contracted renal cell carcinoma and died on January 17, 1929. His ashes were sprinkled over the river Potomac.

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Niacin flush - side effects - cholesterol control

Home > Niacin flush side effects during cholesterol control
Benefits of niacin like increase in good cholesterol and lipid management and control outnumber its side effects - niacin flush.

Niacin, when taken for cholesterol control, in its nicotinic acid form causes reactions which are called 'niacin flush'. The necessity and benefits of niacin in nutrition are well known.
There are other uses of niacin in achieving good health. Niacin, though in its nicotinic acid form has been found to control cholesterol.

Dyslipidemia

Dyslipidemia is the disorder of blood lipid levels. Usually dyslipidemia occurs as an elevation of lipid levels in the blood and is hyperlipidemia .
This increase and the lack of cholesterol control is due to many factors like genes, food habits, malnutrition and lifestyle. The side effects of chronic high levels of insulin is dyslipidemia.

Benefits of niacin in control of cholesterol

To reduce the blood serum lipids there are cholesterol control ways like exercise, regulated diet and medication.
Nicotinic acid helps in the regulation of lipid levels.
Niacin is very effective in lowering triglycerides, serum lipids and in low density cholesterol.
Niacin doses of 500 mg, 1000 mg and even 2 gm are prescribed for lipid control.
In high doses,though there is flush and side effects, serum levels of both 'very low density lipoprotein' (VLDL) and 'low density lipoprotein' (LDL) are reduced and the serum level of 'high density lipoprotein' (HDL) is increased with control of cholesterol .
Clinical trials have demonstrated that nicotinic acid effectively controls progress of atherosclerosis (fat deposits in arteries) and cardiovascular disease.
However it has these very unpleasant side effects.

Causes, signs and symptoms of niacin flush

Cutaneous reddening and pruritus (itch) are side effects of taking higher doses of nicotinic acid in cholesterol control.
Nicotinic acid adverse reactions occurs within 30 minutes of ingestion of the tablet, causing cutaneous reddening of face and neck and trunk.
Side effects like gastrointestinal upset, headache, warmth, tingling and itching of face and the trunk may also occur during flush.
There can be pricking and itching sensations on the body during the side effects.
Particularly the areas of the body which are covered by the dress show more adverse reactions like pricking sensations during the flush.
The side effects are due to dilation of the capillaries in the skin and greater blood flow to the skin.
Earlier it was believed that histamine was the cause of it. However it was found that histamine was not involved in the reactions.
It is found that Prostaglandin is the prime cause for inducing the adverse reactions like flush during cholesterol control; serotonin also has a role in the reactions.
These nicotinic acid symptoms and side effects last for about an hour and then they subside.

Treatment and remedies for niacin flush

Though niacin flush is harmless the severity of the symptoms sometimes deter people from continuing taking niacin effective cholesterol is not achieved.
The symptoms and side effects of 'niacin flush' usually subside after 60 minutes. Tolerance to nicotinic acid develops slowly and the reactions also usually taper off.
It is advised to take two to four split doses to reduce adverse reactions.
It is advised not to do exercise immediately after taking the tablets.
Starting the niacin dosage at low levels and gradually increasing it over a period of time may prevent the severity of side effects.
If there is a break in this treatment for cholesterol control, it is advised to go back to initial low doses and gradually increase it to avoid recurrence of severe side effects.
Taking aspirin or ibuprofen 30 minutes before taking niacin tablet helps in preventing it.
However as these drugs are notorious for stomach irritation and bleeding consult your healthcare provider about the dosage and suitability.
Taking hot beverages or alcohol around the time of niacin consumption may cause severity in these side effects.
Take niacin tablet along with food so that absorption will be slower and may reduce it.
Drinking up to 250 ml of water dilutes the vitamin and adverse reactions  are reduced.
If there are any indications of the start of flush, immediately take plenty of water to stop or to control it.

Say no to 'flush free' or no-flush' niacin

Inositol hexanicotinate is a very efficient vitamin B3 supplement. This vitamin B3 form is being branded and sold as 'flush free' and 'no flush' niacin.
This product is available in 200mg, 500mg and 1000mg strengths as reaction free tablets over the counter. They are only vitamin supplements.
Though it does not cause side effects, cholesterol reduction is not achieved and the purpose is not achieved.
Experiments have proved that, this 'no flush' vitamin B3 has no effects and there is no niacin reactions.
Nicotinamide and niacinamide also are not useful in cholesterol control and hypercholesterolemia management and do not cause side reactions.
The addition of amide group inhibits niacin reactions and vasodilation.
So there is no cholesterol control, no reactions and no side effects.
So the best way is to get around niacin reactions with precautions and control cholesterol for our healthy life.
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Types of proteins


Proteins types are categorized as per their structure, chemical composition and biological function.

Proteins types in relation to the structure

Proteins are made up of long chains of amino acids the sequence of which is decided by gene expression. A simple polypeptide chain of amino acid is called monomeric chain and those with several polypeptide chains and bonds are called oligomeric types. With relation to the structure and number of amino acids present and the nature of bonding, they are broadly categorized into four classes. Primary structure:
This is a basic structure made up of amino acids chains and the sequence is defined by the gene expression.
Secondary structure:
In these proteins covalent bonding within and outside the chains is made and a structure, usually of helix shape, is formed.
Tertiary structure:
In these types of proteins the structure is much more complex.
These structures are three dimensional in nature with complex formations of folds and loops due to repulsion of like charged molecules and attraction of oppositely charged molecules.
Quaternary structure:
These types of proteins are very large complex molecules with many many polypeptide chains. There are two main classes of quaternary structure and they are scleroproteins and globular proteins.
Scleroproteins:
These are also called fibrous proteins. They form long rod or wire-like shaped filaments. these are not soluble in aqueous solutions.
They are usually inert and are storage or structural types of protein having role in supportive and protective function.
They are found in bone matrix, connective tissues, muscle fiber and tendons. Some of the examples of this class are collagen, elastin, keratin and fibroin (in silk).
These are also called spheroproteins having globe like structure and are soluble in aqueous solutions. Many types of enzymes, catalysts, hormones, transporters, signal transduction proteins, plasma, coagulation factors, growth factors and hemoproteins come under this category. Nucleosome, spliceosome, signal recognition particle and ribonucleoprotein are complexes with many components.

Types of proteins based on chemical composition

Depending upon the chemical composition, they are classified as simple or conjugated proteins.
Simple proteins:
Simple types contain only amino acids and do not contain any other chemical or chemical groups.
Conjugated proteins:
Many of these contain apart from amino acids other metal and chemical components and are named conjugated proteins.
The non amino acid parts are called prosthetic groups.
Some of the conjugated types and their prosthetic groups are given below.
Lipoproteins:
These conjugated protein types contain lipids in their biochemical assembly.
Lipid groups may be bound non-covalently or covalently.
Many protein like structural proteins, enzymes, transporters, antigens, toxins, adhesins, HDL (high density lipoproteins), LDL (low density lipoproteins), mitochondria and pathogen lipoprotein are lipoproteins.
Glycoproteins:
These conjugated proteins contain glycans (oligosaccharide chains) covalently attached to the side-chains of polypeptides.
These types are very important in integral membrane proteins.
There are many important glycoproteins like mucins (present in mucus), antibodies (immunoglobulins), glycoprotein llb/llla ( found on blood platelets and required for their aggregation), components of zona pellucida surrounding ovum, structural protein in the connective tissue, egg white, blood plasma, hormones (Follicle-stimulating hormone, Alpha-fetoprotein and Thyroid-stimulating hormone, Luteinizing hormone and Human chorionic gonadotropin and Erythropoietin).
Phosphoproteins:
These are chemically bonded to compounds containing phosphoric acid. Calcineurins are one of the examples.
Hemoproteins:
These conjugated types contain heme prosthetic group bound non covalently or covalently to the proteins.
Heme consists of iron atom contained in the center of a large heterocyclic organic ring called a porphyrin.
Many hemoproteins like hemoglobin, myoglobin, cytoglobin, hemocyanin, neuroglobin and leghemoglobin are required for oxygen transport.
Hemeproteins like peroxidases, ligninases and cytochrome c oxidase have the function of catalysis.
Hemeproteins, cytochrome c and catalase have a role in electron transfer whereas for active membrane transport cytochromes are needed.
Flavoproteins: 
These contain nucleic acid derivative of riboflavin like flavin mononucleotide (FMN) or flavin adenine dinucleotide (FAD).
These have many functions in DNA repair, photosynthesis, apoptosis and cellular respiration.
Metalloproteins:
These types have a metal ion as cofactor.
Many hemeproteins, enzymes (metalloenzymes), signal transduction factors come under these types.
Some of the metals in metalloproteins are iron (hemoglobin), zinc (carbonic anhydrase), cobalt (Vitamin B12 or cobalamin), copper (superoxide dismutase), magnesium (chlorophyll, Hexokinase, Glucose 6-phosphatase, DNA polymerase), calcium (calmodulin), vanadium (vanabins), nickel (Hydrogenase, Urease), manganese (arginase), selenium (Glutathione peroxidase) and molybdenum (nitrate reductase).
Opsins:
Opsins are conjugated types present in photoreceptor cells of the retina.
Opsins bind covalently to vitamin A based retinaldehyde chromophore and function the vision perception.
Other conjugated proteins like cytochrome have function in electron transport and phytochromes function in plants for photoreception regulating photoperiodism, circadian rhythms and germination of seeds.

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What are proteins? - What are proteins made of?

› › › What are Proteins made of?

What are proteins?

Proteins are highly complex compounds made of nitrogenous organic macromolecules comprising a variety of α amino acids which are joined together by peptide bonds.
They are formed by the complex polymerization of amino acids and are essential for every biochemical function of the living organisms.
They are the building blocks of the living beings right from the simple forms like virus to higher animals with complex organ systems.
Nearly 50% of the dry weight of the organisms constitute these complex structures.

What are proteins made of?

Proteins are essentially formed from a number of amino acids which in turn are made of carbon, oxygen and hydrogen.
Nearly all them contain nitrogen and sulphur.
Specialised structures are formed with the incorporation of minerals like phosphorus, copper, zinc and iron.
Proteins molecules are large and have high molecular weights.
Proteins are made from 2-100 numbers of amino acids having molecular weight of about 10kDa are called peptides.
The combination sequence of these amino acids can produce innumerable proteins.
In the E.coli bacteria cell there are 3000 different known varieties.
The optical isomers of alanine, D-Alanine and L-Alanine

They are made of three very important structure levels namely primary, secondary and tertiary.
The primary level is the amino acid sequence and is determined by gene expression.
In the secondary level of structure, the angles of bonds (covalent) within and between the amino acids determines the geometrical shape usually helix.
The tertiary three dimensional level of structure of folds and loops is due to the repulsion of like charged amino acid groups and attraction of oppositely charged amino acid groups.
This structure is usually the basis for the biological activity of proteins. 
They are primarily the organic structure basis of skin, hair, tendons, bones, muscles and cartilage. 
All our organs and body fluids contain and made of them. 
The enzymes, hormones, blood and serum contain them and body functions like digestion, circulation are brought about by them.
Proteins are made from amino acids
Proteins are made with 22 amino acids of which eight are essential amino acids.
These amino acids are considered essential because the body cannot synthesise them.
The rest of the 14 amino acids are synthesised by the adult human body.
Essential amino acids for humans: Isoleucine,Leucine, Lysine, Methionine, Phenylalanine, Threonine, Tryptophan and Valine Amino acids synthesised by adult body: Alanine, Asparagine, Aspartic Acid, Cysteine, Glutamic Acid, Glutamine, Glycine, Proline, Selenocysteine, Serine, Tyrosine, Arginine, Histidine and Pyrrolysine.
Of these cysteine, histidine, tyrosine and arginine are essential for infants and growing children as they are not produced by them.
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