单词	protamine
释义	protamine /ˈprəʊtəmiːn / noun Biochemistry Any of a group of simple proteins found combined with nucleic acids, especially in fish sperm.Sperm chromatin contains protamines that must be replaced by histones before undergoing condensation.... During the process of spermatogenesis in animal species, protamines replace histones and bind sperm DNA. From recent developments in molecular biology, it is becoming clear that cationic chemical species, such as histone octamer, protamine, spermidine, etc. play an essential role in the packing of long DNA chains into the nucleus. Origin Late 19th century: from proto- 'original' + amine.
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