title: Purification and characterization of two fibrinogen-clotting enzymes from five-pace snake (Agkistrodon acutus) venom.
abstract: From the snake venom of Agkistrodon acutus, two proteases, acuthrombin-A and acuthrombin-C, were isolated and purified to homogeneity. They can cleave the human fibrinogen to release the fibrinopeptide A and fibrinopeptide B with specific activity of 120 and 370 NIH units/mg, respectively; the fibrinogen-clotting activity can be inhibited distinctly by PMSF or DFP or EDTA, but not by heparin. The two proteases show also arginine-esterase activity hydrolyzing some synthetic substrates such as TAME and BAEE. Additionally, they are glycoproteins with an average content of 2.4% (acuthrombin-A) and 2.1% (acuthrombin-C) neutral carbohydrates, respectively. Acuthrombin-A has a MW of 13,900 as estimated by SDS-PAGE under reduced or nonreduced conditions and 28,000 as determined by gel filtration. For acuthrombin-C, there were two protein bands corresponding to MW of 13,900 and 14,800 on SDS-PAGE with different darkness under reduced or nonreduced conditions, while its MW was estimated to be 69,000 by gel filtration. The isoelectric points were 7.5 for acuthrombin-A and 5.0 for acuthrombin-C by isoelectric focusing. Neither acuthrombin-A nor acuthrombin-C has haemorrhagic or lethal activity. Acuthrombin-A has also a small amount of activity to activate the Factor XIII.
authors.affiliation: Department of Molecular and Cell Biology, University of Science and Technology of China, Anhui, People's Republic of China.
authors.forename: Q Q
authors.initials: QQ
authors.lastname: Huang
authors.forename: M K
authors.initials: MK
authors.lastname: Teng
authors.forename: L W
authors.initials: LW
authors.lastname: Niu
mesh_terms: D017836:Agkistrodon / Q000378:metabolism*; D000818:Animals; D001777:Blood Coagulation / Q000187:drug effects*; D002850:Chromatography, Gel; D010450:Endopeptidases / Q000302:isolation & purification / Q000494:pharmacology*; D004950:Esterases / Q000378:metabolism; D005176:Factor XIII / Q000378:metabolism; D005340:Fibrinogen / Q000187:drug effects* / Q000378:metabolism; D005344:Fibrinopeptide A / Q000378:metabolism; D005345:Fibrinopeptide B / Q000378:metabolism; D006470:Hemorrhage / Q000139:chemically induced; D006801:Humans; D006868:Hydrolysis; D051379:Mice; D010084:Oxidation-Reduction; D010447:Peptide Hydrolases / Q000494:pharmacology; D011817:Rabbits; D012910:Snake Venoms / Q000737:chemistry / Q000201:enzymology*; D013917:Thrombin / Q000494:pharmacology / Q000633:toxicity
chemical_list: D012910:Snake Venoms; D005344:Fibrinopeptide A; D005345:Fibrinopeptide B; D005340:Fibrinogen; D005176:Factor XIII; D004950:Esterases; D010450:Endopeptidases; D010447:Peptide Hydrolases; D013917:Thrombin