| protein conformation | The characteristic 3-dimensional shape of a protein, imposed upon it by the secondary and tertiary structure of the peptide chain. This stage in the structure of a protein describes the highest level of organization in overall structure assumed by multimeric proteins (aggregates of more than one polypeptide chain). This is the fourth folding level of protein building. (12 Dec 1998) |
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| protein crystallization | This is an essential process in determining a protein's three-dimensional structure, and hence in using that information to design drugs. (14 Nov 1997) |
| protein-D-aspartate methyltransferase | <enzyme> For protein carboxymethylases consider also protein o-methyltransferase Registry number: EC 2.1.1.77 Synonym: d-aspartyl-l-isoaspartyl methyltransferase, protein d-aspartate-l-isoaspartate methyltransferase, protein l-isoaspartate o-methyltransferase, protein-beta-aspartate methyltransferase, protein-l-isoaspartate methyltransferase, protein l-isoaspartyl methyltransferase, isoaspartyl-aspartyl protein methyltransferase, protein-d-asp methyltransferase, l-isoaspartyl protein carboxymethyltransferase, pcm gene product, pcmt1 gene product (26 Jun 1999) |
| protein deficiency | A nutritional condition produced by a deficiency of proteins in the diet, characterised by adaptive enzyme changes in the liver, increase in amino acid synthetases, and diminution of urea formation, thus conserving nitrogen and reducing its loss in the urine. Growth, immune response, repair, and production of enzymes and hormones are all impaired in severe protein deficiency. Protein deficiency may also arise in the face of adequate protein intake if the protein is of poor quality (i.e., the content of one or more amino acids is inadequate and thus becomes the limiting factor in protein utilization). (12 Dec 1998) |
| protein disulfide-isomerase | <enzyme> An enzyme that catalyses the rearrangement of disulfide bonds within proteins during folding. It is a monomer identical to one of the subunits of procollagen-proline dioxygenase. Chemical name: Protein disulfide-isomerase Registry number: EC 5.3.4.1 (12 Dec 1998) |
| protein disulfide reductase (glutathione) | <enzyme> An enzyme that catalyses the reduction of a protein-disulfide in the presence of glutathione, forming a protein-dithiol. Insulin is one of its substrates. Chemical name: Glutathione:protein-disulfide oxidoreductase Registry number: EC 1.8.4.2 (12 Dec 1998) |
| protein-energy malnutrition | The lack of sufficient energy or protein to meet the body's metabolic demands, as a result of either an inadequate dietary intake of protein, intake of poor quality dietary protein, increased demands due to disease, or increased nutrient losses. (12 Dec 1998) |
| protein engineering | Normally means the use of recombinant DNA technology to produce proteins with desired modifications in the primary sequence. See: site specific mutagenesis. (18 Nov 1997) |
| protein factor | The factor (6.25) by which the nitrogen content of a protein is multiplied to give the amount of protein. (05 Mar 2000) |
| protein fever | Fever produced by the injection of foreign protein, such as milk. (05 Mar 2000) |
| protein folding | A rapid biochemical reaction involved in the formation of proteins. It begins even before a protein has been completely synthesised and proceeds through discrete intermediates (primary, secondary, and tertiary structures) before the final structure (quaternary structure) is developed. (12 Dec 1998) |
| protein G | Protein from Group C Streptococci that binds the Fc portion of IgG. Is less species specific than Protein A. (18 Nov 1997) |
| protein geranylgeranyltransferase | <enzyme> Involved in protein isoprenylation; transfers geranylgeranyl group to cys fourth from the c-terminal of GTP-binding proteins; amino acid sequence of beta subunit of ggtase-i known; genbank l24116; see also rab, ras, and rhoa p21 geranylgeranyl- transferases and component a, rab geranylgeranyltransferase Registry number: EC 2.5.1.- Synonym: protein ggtase, geranylgeranyltransferase type-i, ggtase-i, geranylgeranyl-protein transferase type 1 (26 Jun 1999) |
| protein-glutamine gamma-glutamyltransferase | <enzyme> An enzyme that catalyses the reaction of protein glutamine and an alkylamine to yield protein n(5)-alkylglutamine and ammonia. The gamma-carboxamide groups of peptide-bound glutamine residues act as acyl donors, and the 6-amino groups of protein- and peptide-bound lysine residues act as acceptors, to give intra- and inter-molecular n(6)-(5-glutamyl)lysine crosslinks. In the epidermis these cross-linked proteins are involved in the formation of the cornified envelope of the stratum corneum cells. In the plasma, the transglutaminase is called factor xiiia, the activated form of factor xiii. The crosslinking results in the stabilization of the fibrin clot. Pharmacological action: coagulants. Chemical name: Protein-glutamine:amine gamma-glutamyltransferase Registry number: EC 2.3.2.13 (12 Dec 1998) |
| protein-histidine kinase | <enzyme> Sass involved in transduction of starvation and cell density inputs; hkna isolated from bacillus thuringiensis; ciah isolated from streptococcus pneumoniae; do not confuse with plp1 protein Registry number: EC 2.7.3.- Synonym: histidine protein kinase, histidine kinase, hkna gene product, ciah gene product, kinc gene product, prrb gene product, plec gene product, mxcq gene product, rese gene product, hpka gene product, comd gene product, plpa gene product (phytochrome-like), divj gene product, sensor histidine kinase, sass gene product (26 Jun 1999) |