Cassava linamarases for enzymic determination of cyanide

Abstract

Cassava linamarases were readily prepared from leaves and peel by hydrophobic interaction chromatography using Phenyl Sepharose CL-4B. With cassava peel, the filtration step was rate-limiting and it took a longer time than with leaves to prepare the enzyme. Leaf enzyme preparations from 34 cassava varieties yielded 23-103 U/g fresh weight and purity of two- to fivefold. Peel of 14 cassava varieties gave lower yields, ranging from 1-10 U/g. The enzymes from both leaf and peel were similar in terms of their K(m) (p-nitrophenyl β-D-glucoside) values and pH dependence. Some differences were observed in their stability on drying. Enzyme preparations from both sources could be used for the determination of cyanide in cassava, but those from leaves were preferable because of the high yield and activity.