Properties of Rhodanese from the Liver of Tilapia Oreochromis Niloticus, in Asejire Lake, Nigeria

Abstract

The study investigates the purification and characterisation of rhodanese from the liver of the tilapia fish (Oreochromis niloticus) collected from Asejire Lake in Nigeria. This was with a view to understanding the biochemical basis of the survival of the fish in cyanide polluted water. Rhodanese was isolated and purified from liver tissue homogenate of tilapia using CM-Sephadex ion exchange chromatography and Sephadex G-75 gel filtration. The specific activity of the enzyme was 56.86 U/mg. The Km values for KCN and Na2S2O3 as substrates were 0.1240 ± 0.0021 mM and 0.0516 ± 0.0097 mM, respectively. The apparent molecular weight was estimated by gel filtration on a Sephacyl S-400 column to be 35,460 Da. The optimal activity was found at pH 6.5 and the temperature optimum was 40°C. The rhodanese enzyme showed that the activity of the enzyme was not affected by MgCl2, KCl, NH4Cl, MnCl2 and CaCl2 while AlCl3, inhibited the enzyme.