Protamine


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protamine

[′prōd·ə‚mēn]
(biochemistry)
Any of the simple proteins that are combined with nucleic acid in the sperm of certain fish, and that upon hydrolysis yield basic amino acids; used in medicine to control hemorrhage, and in the preparation of an insulin form to control diabetes.

Protamine

 

a protein of low molecular weight that occurs in the nuclei of spermatozoa in fish and birds. Its molecular weight ranges from 4,000 to 12,000.

The basic properties of protamines are determined by their characteristically high content of basic amino acids, especially arginine (70–80 percent). Protamines are readily soluble in water and in acid and neutral media. They are precipitated by alkalies and do not denature when heated. The protamines that have been studied are mainly those found in mature fish spermatozoa, where they constitute a fraction of the basic protein but nearly the entire nuclear protein. The amino-acid composition of protamines is specific for each species of fish.

In cell nuclei, protamines, like histones, are associated with deoxyribonucleic acids to form nucleoprotamines. X-ray diffraction analysis has shown that the protamine chain is the third strand coiled around the DNA double helix. Protamines form salts in the presence of acids and complexes with acid proteins; in medicine, the slightly soluble complex of protamine and insulin is used to prolong the effectiveness of the latter.

References in periodicals archive ?
These proteins are then replaced by more basic proteins named protamine (P1, P2), which are responsible for the final condensation and stabilization of sperm DNA (34) Sperm DNA interacts with protamines so that it converts the coiling of sperm DNA into toroidal subunits so called as "Doughnut loops" (35).
Cationic polymers, such as polylysine, histone, and protamine, are known to complex and condense ON from an extended conformation to highly compact structures of about 30 to 100 nm in diameter.
Our initial experiments revealed that histones and protamines generate a significant interaction with the IRMA for CRH and ACTH.
Further studies should clarify how the stimulation and stabilization of CDC25A mRNA and protein expression, e.g., via the influence of protamine can improve spermatogenesis in infertile men.
On surgical request, for subjective coagulopathy, a further 100 mg of protamine was given and an infusion of another 100 mg was given over two hours, making a total of 500 mg.
Such finding may indicate that protamine deficiency has considerable affect on fertilization rate.
The addition of protamine sulfate (which counteracts heparin activity) to the plasma sample produced the same results as the serum sample and did not lead to error flags, thus confirming that the precipitant formation was attributable to the interaction of lithium heparin with the paraprotein.
The findings also showed that the rate of sperm with protamine deficiency increased in sperm samples from patients with mild male infertility, when compared with the other group (p < 0.01; Figure 1).
Accurate monitoring of blood heparin concentrations can also aid in heparin therapy by providing a means to determine the minimal protamine dose required to neutralize the anticoagulant activity of heparin at the conclusion of CPB.
Contract awarded for 82100520-mixture of 30 percent insulin aspart and 70 percent insulin aspart protamine crystals 100 u per ml 3ml cartridge
ProZinc (protamine zinc recombinant human insulin) has been in use for cats but is now approved for dogs, too.