protein
NounOpen English WordNet
Noun (1)proteins
- any of a large group of nitrogenous organic compounds that are essential constituents of living cells; consist of polymers of amino acids; essential in the diet of animals for growth and for repair of tissues; can be obtained from meat and eggs and milk and legumes“a diet high in protein”Type of macromolecule, supermoleculeKinds antibody, enzyme, fibrin, iodoprotein, ferritin, nucleoprotein, conjugated protein, haptoglobin, filaggrin, prostate specific antigen +15 moreSubstance of meat, legume, egg, milkMade of amino acid, polypeptide
What does it mean? Question 1 of today’s quiz
Webster's Dictionary (1913)
Physiol. Chem. In chemical analysis, the total nitrogenous material in vegetable or animal substances, obtained by multiplying the total nitrogen found by a factor, usually 6.25, assuming most proteids to contain approximately 16 per cent of nitrogen.
Origin: Gr. πρῶτος first: cf. πρωτεῖον the first place.
Physiol. Chem. any polymer of an amino acid joined by peptide (amide) bonds. Most natural proteins have alpha-amino acids as the monomeric constituents. All classical enzymes are composed of protein, and control most of the biochemical transformations carried out in living cells. They may be soluble, as casein, albumins, and other globular proteins, or insoluble (e. g. "structural proteins"), as collagen or keratin. "albumin", an older term for protein, is now used primarily to refer to certain specific soluble globular proteins found in eggs or blood serum, e.g. bovine serum albumin, the main soluble protein in the serum of cattle, used as an enzymatically inert protein in biochemical research. In the 1913 dictionary, protein was defined as: “A body now known as alkali albumin, but originally considered to be the basis of all albuminous substances, whence its name.” [ + ]
Protein crystal. Botany See Crystalloid, noun, 2.
Webster’s Revised Unabridged Dictionary (1913), from GCIDE 0.54 · with additions: 1913 supplement, GCIDE editors