inhibition of dehydrogenases by snake venom

Abstract

In continuation of previous studies on the inhibitory effect of snake venoms on glycolysis and fermentation (Quart. J. exp. Physiol. 26, 299; 27, 50; 27, 375) the effect of black tiger snake venom (Notechis scutatus) on the following dehydrogenases and oxidases was tried: lactic, malic, [beta]-hydroxybutyric, amino acid, [alpha]-glycerophosphate, succinic dehydrogenases; cytochrome, xanthine, uric acid oxidases. The venom inactivated in small concs. those dehydrogenase systems the action of which was dependent on the presence of a coenzyme of nucleotide nature. The inactivation was due to a destruction of the coenzymes by the venom. The destruction was an enzymatic process caused by the action of a nucleotidase which was present in many venoms. The nucleotidase acted on coenzyme I (pyridine-di-phos-phonucleotide) by hydrolysing the pyrophosphate linkage in the molecule. In view of the fact that the metabolism of the brain was mainly a carbohydrate metabolism which was especially dependent on the presence of coenzyme I, the neurotoxic effect of the venom was probably due to its destructive action on this substance.