Abstract
It has been reported that diphosphopyridine nucleotide is decomposed by snake-venom enzyme to form nicotinamide but there has been no proof that this decomposition is effected by diphosphopyridinenucleotidase. This nucleotidase activity was examined in nine kinds of Formosan snake venom and the presence of this diphosphopyridinenucleotidase was found in the venom of Bungarus multicinctus and Trimeresurus gramineus. The nature of this nucleotidase of snake venom was also examined and this activity was found to be inhibited non-competitively by nicotinamide and isonicotinic hydrazide. This enzyme also possesses transglycosidase activity and produces isonicotinic hydrazide-diphosphopyridine nucleotide from these two components. The diphosphopyridinenucleotidase in the venom of Trimeresurus gramineus was purified by column chromatography using carboxymethyl- and diethylaminoethylcellulose, and a sample with six-fold increase in specific activity was obtained. This sample is totally free from phosphodiesterase.
