ISSN: 0974-276X
Agboola Femi Kayode
Obafemi Awolowo University, Nigeria
Posters & Accepted Abstracts: J Proteomics Bioinform
Objective: The objective of this study is to purify ?²-cyanoalanine synthase from germinating seeds of sorghum to electrophoretic homogeneity and then determine its biochemical and catalytic properties. Methodology: ?²-cyanoalanine synthase was isolated from sorghum seeds, purified using chromatographic techniques and its biochemical and catalytic properties determined. Result: The purified enzyme had a yield of 61.74% and specific activity of 577.50 nmol H2S/min/mg of protein. The apparent and subunit molecular weight were 58.26?±2.41 kDa and 63.4 kDa. The kinetic parameters with sodium cyanide as substrate were 0.67?±0.08 mM, 17.60?±0.50 nmol H2S/ml/min, 2.97x10-1 s-1 and 4.43x102 M-1s-1 for KM, Vmax, kcat and kcat/KM respectively. With L-cysteine as substrate, the kinetic parameters are 2.64?±0.37 mM, 63.41?±4.04 nmol H2S/ml/min, 10.71x10-1 s-1 and 4.06x102 M-1s-1. The optimum temperature and pH for activity were 35â°C and pH 8.5 respectively. The activation energy obtained was 131.75 J/mol/K. The enzyme retained more than half of its activity at 40â°C. Both monovalent and divalent ions enhanced enzyme activity. Inhibitors such as HgCl2, EDTA, glycine and iodoacetamide reduced enzyme activity. Conclusion: The biochemical properties of the purified ?²-cyanoalanine synthase in germinating sorghum seeds highlight its roles in maintaining cyanide homeostasis.