甲磺隆水解酶酶促反应体系的建立与特性研究

在室内控制条件下对甲磺隆降解菌S113(Methylopila sp.)的水解酶进行了研究,发现该酶为胞内酶、非诱导酶。建立了甲磺隆水解酶的酶促反应体系:2 830 μL Na2HPO4-NaH2PO4缓冲液(0.2 mol/L,pH 7.0),150 μL甲磺隆(1 000 mg/L),20 μL粗酶液(约1.2 μg粗蛋白),30℃水浴30 min。甲磺隆水解酶pH值稳定范围为6~9,最适pH值为8.0。水解酶热不稳定,45℃处理30 min,酶活下降59.22%,70℃处理30 min可完全灭活。测定了8种金属离子对水解酶的作用,发现 1 mmol/L 的Ca2+对酶活有促进作用。

Study on Reaction System and Characteristics of Metsulfuron-methyl Hydrolase

Metsulfuron-methyl hydrolase from metsulfuron-methyl degrading strain S113 (Methylopila sp.) was studied. The hydrolase in the bacterium was endoemzyme. The enzymatic reaction system was found as follows: Na2HPO4-NaH2PO4 buffer 2 830 μL, metsulfuron-methyl (1 000 mg/L) 150 μL, crude enzyme 20 μL (about 1.2 μg crude protein), 30℃ water bathing 30 min. The characteristics of metsulfuron-methyl hydrolase was determined. The pH suitable for keeping enzyme was 6~9, with the optimum pH 8.0. The activity of enzyme was down to 59.22% and zero when treated at 45℃ for 30 min and 70℃ for 30 min, respectively. Eight metal ions were chosen to study their effects on the metsulfuron-methyl hydrolase activity, and the result showed that 1 mmol/L Ca2+ can enhance the enzyme activity.