Effects of temperature, pH, and inhibitors on the procoagulant characterization of FIa, a factor X activator from the venom of Daboia russellii siamensis (Myanmar)

• Published in: Archives of pharmacal research Vol. 33; no. 7; pp. 1043 - 1048
• Main Authors: Sun, Huanhuan, Ma, Haiqing, He, Guangyao, Chen, Jiashu, Qiu, Pengxin, Yan, Guangmei
• Format: Journal Article
• Language: English
• Published: Heidelberg Pharmaceutical Society of Korea 01.07.2010; 대한약학회
• Subjects: Animals; Blood Coagulation Factor Inhibitors - pharmacology; Daboia; Edetic Acid - pharmacology; Factor X - metabolism; Humans; Hydrogen-Ion Concentration; Medicine; Metalloendopeptidases - antagonists & inhibitors; Metalloendopeptidases - isolation & purification; Metalloendopeptidases - pharmacology; Myanmar; Pharmacology/Toxicology; Pharmacy; Protease Inhibitors - pharmacology; Proteins - antagonists & inhibitors; Proteins - isolation & purification; Proteins - pharmacology; Temperature; Viper Venoms - antagonists & inhibitors; Viper Venoms - isolation & purification; Viper Venoms - pharmacology; 약학; Myanmar; Factor X activator; Snake venom; Metalloproteinase
• ISSN: 0253-6269; 1976-3786
• DOI: 10.1007/s12272-010-0710-7

FIa, a factor X activator, was isolated from the venom of Daboia russellii siamensis (Myanmar) after a series of chromatographic separations. FIa displayed procoagulant activity by shortening plasma recalcification time and converted human factor X (FX) to activated human factor X (FXa) by cleaving the heavy FX chain, possibly at the Arg51-Ile52 peptide. FIa was positive in a glycoprotein staining test, demonstrating that it is a glycoprotein. Optimal temperature and pH values were important for FIa procoagulant activity. Procoagulant activity was maintained above 85% of the initial activity at pH 7.0∼8.0, and showed equally maximum activity at temperatures ranging from 30 to 50°C. In addition, FIa procoagulant activity was completely inhibited by EDTA (5 mM), but not by PMSF (10 mM), suggesting that it is a metalloproteinase.