Abstract

Y. Saidu

Rhodanese is a multifunctional, mitochondrial, sulphur transferase that catalyses the detoxification of cyanide by sulphuration in a double displacement (ping pong) mechanistic reaction. It is widely distributed occurring in varieties of plants and animals, where it activity is modulated by a number of factors including differences in species, organs, sex, age and diet. The enzyme is a single polypeptide chain of 289 amino acids with molecular weight of up to 37,000. The active site of rhodanese contains a tryptophanyl residue in close proximity with an essential sulphahydryl group. Many methods for assaying rhodanese have been reported, the most prominent being the one based on the colorimetric estimation of thiocyanate formed from the reaction of cyanide and thiosulphate, catalysed by rhodanese.