Canadian Medical Guide > Chemicals and Drugs > Amino Acids, Peptides, and Proteins > Peptides > Oligopeptides Terms and Definitions

Oligopeptides

Medical Definition:	Peptides composed of between two and twelve amino acids.
Guide Notes:	2-12 amino acids (includes DIPEPTIDES, tripeptides, tetrapeptides, pentapeptides, etc.); GEN; prefer specifics; conformation: coord OLIGOPEPTIDES or specific peptide (IM) + PROTEIN CONFORMATION (NIM)
Previously Indexed:	Peptides (1966-1972)

Oligopeptides Categories.

	Amanitins - Cyclic peptides extracted from carpophores of various mushroom species. They are potent inhibitors of RNA polymerases in most eukaryotic species, blocking the production of mRNA and protein synthesis. These peptides are important in the study of transcription. Alpha-amanitin is the main toxin from the species Amanitia phalloides, poisonous if ingested by humans or animals.
	Antipain - An oligopeptide produced by various bacteria which acts as a protease inhibitor.
	Caerulein - A specific decapeptide obtained from the skin of Hila caerulea, an Australian amphibian. Caerulein is similar in action and composition to CHOLECYSTOKININ. It stimulates gastric, biliary, and pancreatic secretion; and certain smooth muscle. It is used in paralytic ileus and as diagnostic aid in pancreatic malfunction.
	Dipeptides - Peptides composed of two amino acid units.
	Glutathione - A tripeptide with many roles in cells. It conjugates to drugs to make them more soluble for excretion, is a cofactor for some enzymes, is involved in protein disulfide bond rearrangement and reduces peroxides.
	Leupeptins - A group of acylated oligopeptides produced by Actinomycetes that function as protease inhibitors. They have been known to inhibit to varying degrees trypsin, plasmin, KALLIKREINS, papain and the cathepsins.
	Netropsin - A basic polypeptide isolated from Streptomyces netropsis. It is cytotoxic and its strong, specific binding to A-T areas of DNA is useful to genetics research.
	Pepstatins - N-acylated oligopeptides isolated from culture filtrates of Actinomycetes, which act specifically to inhibit acid proteases such as pepsin and renin.
	Peptide T - N-(N-(N(2)-(N-(N-(N-(N-D-Alanyl L-seryl)-L-threonyl)-L-threonyl) L-threonyl)-L-asparaginyl)-L-tyrosyl) L-threonine. Octapeptide sharing sequence homology with HIV envelope protein gp120. It is potentially useful as antiviral agent in AIDS therapy. The core pentapeptide sequence, TTNYT, consisting of amino acids 4-8 in peptide T, is the HIV envelope sequence required for attachment to the CD4 receptor.
	Phalloidine - Very toxic polypeptide isolated mainly from Amanita phalloides (Agaricaceae) or death cup; causes fatal liver, kidney and CNS damage in mushroom poisoning; used in the study of liver damage.
	Teprotide - A synthetic nonapeptide (Pyr-Trp-Pro-Arg-Pro-Gln-Ile-Pro-Pro) which is identical to the peptide from the venom of the snake, Bothrops jararaca. It inhibits kininase II and ANGIOTENSIN I and has been proposed as an antihypertensive agent.
	Tuftsin - N(2)-((1-(N(2)-L-Threonyl)-L-lysyl)-L-prolyl)-L-arginine. A tetrapeptide produced in the spleen by enzymatic cleavage of a leukophilic gamma-globulin. It stimulates the phagocytic activity of blood polymorphonuclear leukocytes and neutrophils in particular. The peptide is located in the Fd fragment of the gamma-globulin molecule.

Oligopeptides Medical Definitions and Terms

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