Gaikwad S M, More M W, Vartak H G, Deshpande V V
Division of Biochemical Sciences, National Chemical Laboratory, Pune, India.
Biochem Biophys Res Commun. 1988 Aug 30;155(1):270-7. doi: 10.1016/s0006-291x(88)81079-9.
Modification of glucose/xylose isomerase from Streptomyces sp. NCIM 2730 by diethylpyrocarbonate (DEPC) or its photo-oxidation in presence of rose bengal or methylene blue caused rapid loss in its activity. The inactivation of the enzyme was accompanied by an increase in the absorbance at 240 nm and was reversed by hydroxylamine. Glucose and xylose but not Mg++ and Co++ afforded significant protection to the enzyme from inactivation by DEPC. Inactivation followed pseudo-first-order kinetics and modification of a single histidine residue per mole of enzyme was indicated.
焦碳酸二乙酯（DEPC）对链霉菌属NCIM 2730的葡萄糖/木糖异构酶进行修饰，或在孟加拉玫瑰红或亚甲蓝存在下对其进行光氧化，都会导致该酶活性迅速丧失。酶的失活伴随着240nm处吸光度的增加，且可被羟胺逆转。葡萄糖和木糖而非Mg++和Co++能为该酶提供显著保护，使其免受DEPC的失活作用。失活遵循假一级动力学，表明每摩尔酶有一个组氨酸残基被修饰。
