title: A novel prothrombin activator from the venom of Micropechis ikaheka: isolation and characterization.
abstract: A novel prothrombin activator, Mikarin, has been isolated from Micropechis ikaheka venom. It is a single polypeptide chain metalloproteinase with the apparent molecular weight of 47kDa. Mikarin exhibits Ca(2+)-independent prothrombin activation, but no effects on other blood coagulation factors, such as factor X and fibrinogen. Mikarin is the first member of group I prothrombin activators from elapid venom. Like other high-molecular-weight snake venom proteinases, it has three structural domains, metalloproteinase and disintegrin-like and Cys-rich domains, and belongs to the P-III class of snake venom metalloproteinases. The N-terminal of Mikarin exhibits 76% sequence identity with Cobrin, a metalloproteinase identified from Naja naja venom, but very lower identities were found when compared with those from viperid and crotalid venom. In addition, the presence of disintegrin-like and Cys-rich domains in snake venom metalloproteinases with diverse biological activities suggests that these domains may be important for their function.
authors.affiliation: Venom and Toxin Research Programme, Department of Anatomy, Faculty of Medicine, National University of Singapore, 10 Kent Ridge Crescent, 119260, Singapore, Singapore.
authors.forename: Rong
authors.initials: R
authors.lastname: Gao
authors.forename: R
authors.initials: R
authors.lastname: Manjunatha Kini
authors.forename: P
authors.initials: P
authors.lastname: Gopalakrishnakone
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002118:Calcium / Q000494:pharmacology; D004546:Elapid Venoms / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology; D017815:Elapidae; D004789:Enzyme Activation; D005340:Fibrinogen / Q000378:metabolism; D005612:Freeze Drying; D006801:Humans; D008666:Metalloendopeptidases / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology; D008969:Molecular Sequence Data; D008970:Molecular Weight; D011516:Prothrombin / Q000187:drug effects* / Q000378:metabolism; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
chemical_list: D004546:Elapid Venoms; D011516:Prothrombin; D005340:Fibrinogen; D008666:Metalloendopeptidases; C470506:mikarin; D002118:Calcium