Purification and Characterization of Glucose-6-Phosphate Dehydrogenase from Pigeon Pea (Cajanus cajan) Seeds

• 作者: Pramod Kumar Srivastava Siddhartha Singh
• 来源期刊: 酶研究进展(英文)
• 学科: 医学
• 关键词: Purification Characterization Enzyme Glucose-6-Phosphate DEHYDROGENASE PIGEON PEA
• 年，卷（期）: myjjzyw_2014,（4）
• 页码范围: 134-149
• 页数: 16页
• 分类号: R73

摘要

Glucose-6-phosphate dehydrogenase has been purified from pigeon pea (Cajanus cajan) seeds and subjected to characterization. The enzyme was purified 123.69 fold with a yield of 21.37% by ammonium sulphate fractionation, PEG-4000 precipitation, CM cellulose column chromatography and DEAE cellulose column chromatography. The catalytically active enzyme is a dimer of 113 KDa with a subunit molecular weight of 55 KDa. Thermal inactivation of enzyme follows first order kinetics at 30&#176C and 40&#176C with half life of 6 and 1.5 min respectively. Km value for glucose-6-phosphate and NADP+ was found to be 2.68 mM and 0.75 mM respectively whereas Vmax value was found to be 0.11 U/mL and 0.13 U/mL respectively. The enzyme shows more affinity towards NADP+ than glucose-6-phosphate. The pKa value was found to be 10.41 indicating that the amino acid residue at active site might be lysine. The enzyme exhibited maximum catalytic activity at pH 8.2. The enzyme was found to be highly thermosensitive with gradual loss of activity above 30&#176C temperature.