A thrombin-like enzyme with a new amino-terminal sequence was isolated from the venom of Trimeresurus flavoviridis using Q-Sepharose, CM-Cellulose, and HW55 column chromatographies. Homogeneity was confirmed by the formation of a single band in polyacrylamide gel electrophoresis. The enzyme has a molecular weight of 29,000 Da. This thrombin-like enzyme was inhibited by p-amidinophenylmethanesulfonyl fluoride hydrochloride (p-APMSF), and dithiothreitol (DTT) suggesting that serines and disulfide bonds are involved in the expression of the enzyme's clotting activity. This thrombin-like enzyme hydrolyzes the Aalpha-chain and Bbeta-chain of bovine fibrinogen. The enzyme was stable to heat treatment.