Also found in: Dictionary, Thesaurus, Encyclopedia, Wikipedia.
Related to proteins: Amino acids


Large molecules consisting of up to thousands of AMINO ACIDS linked together by peptide bonds to form polypeptides which, in turn, are linked to form proteins. These long chains of amino acids are often folded in specific ways. Fibrous proteins, such as COLLAGEN, are formed from spiral strand polypeptides. They are insoluble and constitute much of the structure of the body. Globular proteins are soluble and include the ENZYMES, many of the hormones and the blood proteins such as haemoglobin and the IMMUNOGLOBULINS (antibodies). Conjugated proteins contain other constituents such as sugars (glycoproteins) and lipids (lipoproteins). See also ABC TRANSPORTER PROTEINS, ACTIN BINDING PROTEINS, ACUTE PHASE PROTEINS, ALPHAFETOPROTEIN, AMYLOID, AMYLOID PRECURSOR PROTEIN, ANNEXINS, ANTIBODY, CHAPERONES, CHEMOKINES, COMPLEMENT, CONFORMATIONAL EPITOPE, CORE OCTAMER, CYTOKINES, DENATURATION, ELASTINS, FIBROBLAST, GLUTEN, GLYCOPROTEINS, G PROTEINS, GRANINS, HEAT-SHOCK PROTEINS, INTERMEDIATE FILAMENT PROTEINS, KERATIN, LECTINS, LIGAMENTS, LIPOPROTEINS, MEMBRANE-PROTEIN ION CHANNELS, MOTOR PROTEINS, MUSCLE, PLASMA PROTEINS, POLYMER, PRION PROTEINS, PROTEASE, PROTEIN BINDING, PROTEIN FOLDING, PROTEIN SYNTHESIS, REPRESSOR PROTEIN, RNA, SINGLE STRAND BINDING PROTEINS, TAU PROTEINS, TERTIARY STRUCTURE AND UBIQUITIN.


large polymers consisting of one or more sequences of amino acid subunits joined by peptide bonds: the major functional and structural components of body cells. The body of a 70 kg man contains about 11 kg protein. The protein mass can be influenced by nutritional status, physical activity and pathological factors. Proteins in the diet typically account for 10-15% of energy intake and the currently recommended protein requirement for sedentary individuals is 0.8 g per kilogram body mass per day. The optimal protein intake for strength athletes may be as high as 1.7-1.8 g and for endurance athletes 1.2-1.4 g per kilogram body mass per day. See also nitrogen balance.

proteins, macromolecules made of up of amino acids joined by peptide linkages and that provide essential life functions. Major sources of dietary proteins include meat, fowl, fish, eggs, beans, seeds, nuts, legumes, and dairy products.

Patient discussion about proteins

Q. I get about 190 grams of protein a day. Is that too much protein? Have you ever seen a guy living only for food? No? Here I am. I get about 190 grams of protein a day. Is that too much protein? My weight is 183 pounds.

A. this is a good amount, just make sure that you get the majority of it from real foods and not from powders and bars.

Q. Does the cooking have a negative effect on the protein content of the food? I have heard that high temperatures cooking breaks the protein, so does the cooking have a negative effect on the protein content of the food?

A. Yes. Proteins can be denatured by heat, but only when the protein structure is delicate or is exposed to extremely high temperatures for long time. You must remember that breaking of protein is the physical-chemical process where the physical or chemical structure of a protein is rearranged. So cooking will not reduce on the nutritive value of the food until it’s cooked at cooking temperatures.

Q. Is it true that Casein protein can cause Cancer, or is harmful to the human body? Someone left a comment on my blog about Casein protein being bad for the body and that it could lead to Cancer. Is this true?

A. I am not familiar with such information, Casein is a protein that is found in large amounts in breastmilk and milk products replacements for babies and as far as I know it has no such affect.

More discussions about proteins
References in periodicals archive ?
Despite Shortcomings Soy Proteins Dominate the Protein Market 10
The V proteins of paramyxoviruses bind the IFN-inducible RNA helicase, mda-5, and inhibit its activation of the IFN-beta promoter.
The authors also analyzed surface structures in proteins that are cross-reactive.
The technique opens a new dimension of study for proteins, says biophysicist Matthias Rief of the Technology University of Munich.
In partnership with scientists at the Brain Research Centre at the University of British Columbia, Kinexus exploited its commercial Kinetworks(TM) phosphoprotein profiling service to discover a novel phosphorylation site on the abundant nuclear protein B23 (also known as nucleophosmin).
Part 2 illustrates the analysis and modification of proteins, with chapters on testing protein functionality, modelling protein behaviour, extracting and purifying proteins and reducing their allergenicity.
The impact of protein intake on renal function decline in women with normal renal function or mild insufficiency.
A number of productive structural investigations of proteins of industrial importance were undertaken, e.
During the workout or game, a breakdown of protein synthesis will occur and this breakdown does not cease when the activity stops.
A simple and reliable method for estimation of protein content in latex called the Latex dotMetric protein assay has been developed.
This report examines each of the protein therapeutics classes in turn, assessing the market potential, and encompassing main therapeutic areas to which they are applicable.
Other features common to paramyxovirus fusion proteins, type I transmembrane glycoproteins, are a signal sequence, a transmembrane domain, and 2-heptad repeats.