protamine

Any of a class of proteins, highly basic because rich in l-arginine and simpler in constitution than the albumins and globulins, etc., found in fish spermatozoa in combination with nucleic acid; the protamines have a histonelike function and are present in the sperm of all mammals; neutralizes anticoagulant action of heparin; used in the preparation of several long-acting insulin preparations.

- p. sulfate a purified mixture of simple protein principles from the sperm or testes of suitable species of fish; it is a heparin antagonist used in certain hemorrhagic states associated with increased amounts of heparin-like substances in the circulation and for the treatment of heparin overdosage.

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prot·amine 'prōt-ə-.mēn n any of various strongly basic proteins of relatively low molecular weight that are rich in arginine and are found associated esp. with DNA in place of histone in the sperm of various animals (as fish)

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n.

one of a group of simple proteins that can be conjugated with nucleic acids to form nucleoproteins. Protamine can also be combined with insulin and zinc to form protamine zinc insulin, which - when injected - is absorbed much more slowly than ordinary insulin and thus reduces the frequency of injections. See also isophane insulins.

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pro·ta·mine (proґtə-mēn) [prot- + amine] any of a class of basic proteins of low molecular weight, occurring in combination with nucleic acids in the sperm of salmon and certain other fish and having the property of neutralizing heparin.