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.