Physicochemical properties of rhodanese: A cyanide detoxifying enzyme from Pentadiplandra brazzeana (Baill) root

Abstract

Rhodanese a ubiquitous sulphur transferase enzyme catalyses the detoxification of cyanide to a less toxic thiocyanate. Rhodanese from the root of Pentadiplandra brazzeana was purified by ammonium sulphate precipitation and affinity chromatography. The enzyme had a specific activity of 4.82 RU/mg of protein. The K m values of the substrates (KCN and Na 2 S 2 O 3 ) were 11.76 and 10 mM, respectively. The optimum pH and temperature of the enzyme activity were 8.0 and 60°C, respectively. The enzyme was not inhibited by the heavy metals (BaCl 2 , KCl, NiCl 2 , NaCl, MnCl 2 , and ZnCl 2 ). This study affirmed the presence of rhodanese in the root of P. brazzeana, an indication that the plant may be of useful biotechnological application, especially in bioremediation of cyanide intoxified farm sites.