title: Biochemical properties and comparative pharmacology of a coagulant from Deinagkistrodon acutus snake venom.
abstract: A number of snake venom thrombin-like enzymes (TLEs) have already been characterized. Some TLEs play significant roles in vessel injury hemostasis. A novel TLE (Agacutase) was purified from Deinagkistrodon acutus snake venom by the means of Sephadex G-75, DEAE-Sepharose FF, and Sephadex G-25 column chromatography. Structural analysis indicated that Agacutase is a single-chain glycoprotein with a molecular mass of 31,084 Da, isoelectric point of 4.38, optimal activity at 37 °C and pH 6.6, sugar content of 7.6%. Its N-terminal 44 amino acid sequence was determined to be VIGGNECDTNEHRFLAAFFTSRPWIFQCAGTLIHEEWVLAAAHC, showing maximum identity of 80% with that of Dav-X protease. The Agacutase-induced clotting activity was not influenced by heparin, hirudin, or Dextran 40, but activated by Ca(2+) and inhibited by PMSF or lactose, which suggests that Agacutase is a serine protease and the coagulation activity is independent of Thrombin. Agacutase with arginine esterase activity specifically cleaves the α-chain of fibrinogen. Agacutase iv (0.03-0.12 U/kg) shortened 16-68% of the rabbit blood clotting time. No significant influence was indicated on platelet, Factor II and XIII, or fibrinolytic system. It converts fibrinogen into the soluble fibrin that accelerates hemostasis at wound. Pharmacological comparison showed the hemostatic effect of Agacutase lasted 24h while Reptilase did 8h. Its maximum tolerated, abnormal toxicity, allergic, and hemorrhagin doses were 80 U/kg, 1 U, 2 U, and 50 U, respectively, whereas those of Reptilase or Agacutin were 35 U/kg, 0.25 U, 0.25 U, and 0.2 U, respectively. The results indicated that Agacutase may be a predominant coagulant.
authors: Guangdong Key Laboratory of Pharmaceutical Bioactive Substances, School of Basic Courses, Guangdong Pharmaceutical University, Guangzhou 510006, China. Electronic address: songstang@gmail.com.
authors: Song-Shan
authors: SS
authors: Tang
authors: Department of Biochemistry, Guangzhou Medical College, Guangzhou 510009, China.
authors: Xiao-Hua
authors: XH
authors: Wang
authors: Department of Obstetrics & Gynecology, Guangdong Provincial Corps Hospital, Guangzhou 510507, China.
authors: Juan-Hui
authors: JH
authors: Zhang
authors: Department of Hematology, Zhujiang Hospital, Southern Medical University, Guangzhou 510280, China.
authors: Bo-Shan
authors: BS
authors: Tang
authors: Department of Biochemistry, China Pharmaceutical University, Nanjing 210009, China.
authors: Li
authors: L
authors: Qian
authors: Guangdong Key Laboratory of Pharmaceutical Bioactive Substances, School of Basic Courses, Guangdong Pharmaceutical University, Guangzhou 510006, China.
authors: Pei-Ying
authors: PY
authors: Li
authors: Guangdong Key Laboratory of Pharmaceutical Bioactive Substances, School of Basic Courses, Guangdong Pharmaceutical University, Guangzhou 510006, China.
authors: Lie-Wei
authors: LW
authors: Luo
mesh_terms: D017836:Agkistrodon; D000818:Animals; D001777:Blood Coagulation / Q000187:drug effects*; D003029:Coagulants / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D003435:Crotalid Venoms / Q000008:administration & dosage / Q000737:chemistry / Q000201:enzymology* / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D051379:Mice; D011817:Rabbits; D012697:Serine Endopeptidases / Q000008:administration & dosage / Q000737:chemistry / Q000378:metabolism*; D013329:Structure-Activity Relationship
chemical_list: C031442:Agkistrodon venoms; D003029:Coagulants; D003435:Crotalid Venoms; D012697:Serine Endopeptidases; C000601123:agacutase protein, Deinagkistrodon acutus