Protamines are small, arginine-rich, nuclearproteins that replace histones late in the haploid phase of spermatogenesis and are believed essential for sperm head condensation and DNA stabilization. They may allow for denser packaging of DNA in spermatozoon than histones, but they must be decompressed before the genetic data can be used for protein synthesis. However, in humans and maybe other primates, 10-15% of the sperm's genome is packaged by histones thought to bind genes that are essential for early embryonic development.
When mixed with insulin, protamines slow down the onset and increase the duration of insulin action (see NPH insulin).
Protamine is used in cardiac surgery, vascular surgery, and interventional radiology procedures to neutralize the anti-clotting effects of heparin. Adverse effects include increased pulmonary artery pressure and decrease peripheral blood pressure, myocardial oxygen consumption, cardiac output, and heart rate.
In gene therapy, protamine sulfate's ability to condense plasmid DNA along with its approval by the U.S. Food and Drug Administration (FDA) have made it an appealing candidate to increase transduction rates by both viral and nonviral (e.g. utilizing cationic liposomes) mediated delivery mechanisms.
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