Purification and characterization of rhodanese from sprouted maize

Rhodanese, a cyanide detoxifying enzyme, was isolated and partially purified from malted maize (Zea

mays) using 85% ammonium sulphate precipitation and ion-exchange chromatography on CM-

Sephadex C-25. The specific activity of the enzyme obtained was 5.07RU/mg protein with a yield of

9.6% and purification fold of 2.13. The Michaelis constant (Km) values of the substrates sodium

thiolsulphate (Na2S2O3) and potassium cyanide (KCN) were 80 mM and 300mM while their Vmax were

4.86 RU/ml/min and 10.2 RU/ml/min respectively. The enzyme had higher substrate specificity of

100% activity to Sodium thiosulfate than other substrate. The optimum pH and temperature of the

enzyme were 8.0 and 60oC. The enzyme was found to be stable up to 60oC for 40 min. The chloride of

potassium (KCl) at 0.01 and 0.001 M had no effect on the activity of rhodanese from malted maize.

This research showed that rhodanese activity is present in malted maize (Zea mays).

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