| repressor proteins | Proteins which are normally bound to the operator locus of an operon, thereby preventing transcription of the structural genes. In enzyme induction, the substrate of the inducible enzyme binds to the repressor protein, causing its release from the operator and freeing the structural genes for transcription. In enzyme repression, the end product of the enzyme sequence binds to the free repressor protein, the resulting complex then binds to the operator and prevents transcription of the structural genes. (12 Dec 1998) |
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| cerebrospinal fluid proteins | Proteins in the cerebrospinal fluid, normally albumin and globulin present in the ratio of 8 to 1. Increases in protein levels are of diagnostic value in neurological diseases. (brain and bannister's clinical neurology, 7th ed, p221) (12 Dec 1998) |
| membrane proteins | Proteins which are found in membranes including cellular and intracellular membranes. They consist of two types, peripheral and integral proteins. They include most membrane-associated enzymes, antigenic proteins, transport proteins, and drug, hormone, and lectin receptors. (12 Dec 1998) |
| retroviridae proteins | Proteins from the family retroviridae. The most frequently encountered member of this family is the rous sarcoma virus protein. (12 Dec 1998) |
| retroviridae proteins, oncogenic | Retroviral proteins that have the ability to transform cells. They can induce sarcomas, leukaemias, lymphomas, and mammary carcinomas. Not all retroviral proteins are oncogenic. (12 Dec 1998) |
| chimeric proteins | Proteins in individuals that are derived from genetically different zygotes. (12 Dec 1998) |
| peripheral proteins | Pathways that can be easily removed from a biomembrane (e.g., by altering the pH or the ionic strength). Synonym: extrinsic proteins. (05 Mar 2000) |
| periplasmic binding proteins | Transport proteins located within the periplasmic space. Some act as receptors for bacterial chemotaxis, interacting with MCPs. Their mode of action is unclear. (18 Nov 1997) |
| ribosomal proteins | Proteins found in ribosomes. They are believed to have a catalytic function in reconstituting biologically active ribosomal subunits. (12 Dec 1998) |
| growth associated proteins | <growth factor> Group of developmentally regulated polypeptides thought to be critical for the formation of neural circuitry. The acidic membrane phosphoprotein GAP 43 is synthesised and transported down regenerating and developing axons, pp46 localised in growth cone membranes during embryogenesis, B 50 in mature presynaptic membranes in the regulation of phosphotidylinositol turnover and F1 in the hippocampus during long-term potentiation, are now all known to be the same protein. (18 Nov 1997) |
| RNA-binding proteins | Proteins which bind to RNA molecules. Certain structure motifs are common to several of the proteins, such as arginine (arg)-rich tracts, typically consisting of alternating arg-asp, arg-ser, or arg-gly residues. These proteins also tend to have a common ribonucleotide sequence domain. (12 Dec 1998) |
| cholesterol ester transport proteins | A protein that transports cholesterol esters from HDL to VLDL and LDL; a deficiency of this protein is associated with elevated HDL cholesterol. (05 Mar 2000) |
| chromosomal proteins, non-histone | Nucleoproteins which in contrast to histones are acid insoluble. They are involved in chromosomal functions; e.g. They bind selectively to DNA, stimulate transcription resulting in tissue-specific RNA synthesis and undergo specific changes in response to various hormones or phytomitogens. (12 Dec 1998) |
| microfilament proteins | Filaments which are composed primarily of actin and found in the cytoplasmic matrix of almost all cells. They are often associated with microtubules and may play a role in cytoskeletal function and/or mediate movement of the cell or the organelles within the cell. (12 Dec 1998) |
| microtubule-associated proteins | <protein> High molecular weight proteins found in the microtubules of the cytoskeletal system. Under certain conditions they are required for tubulin assembly into the microtubules and stabilise the assembled microtubules. Acronym: MAP (12 Dec 1998) |