Munnecke D M
Appl Environ Microbiol. 1976 Jul;32(1):7-13. doi: 10.1128/aem.32.1.7-13.1976.
A crude cell extract from a mixed bacterial culture growing on parathion, an organophosphate insecticide, hydrolyzed parathion (21 C) at a rate of 416 nmol/min per mg of protein. This rate of enzymatic hydrolysis, when compared with chemical hydrolysis by 0.1 N sodium hydroxide at 40 C, was 2, 450 times faster. Eight of 12 commonly used organophosphate insecticides were enzymatically hydrolyzed with this enzyme preparation at rates ranging from 12 to 1,360 nmol/min per mg of protein. Seven pesticides were hydrolyzed at rates significantly higher (40 to 1,005 times faster) than chemical hydrolysis. The pH optimum for enzymatic hydrolysis of the eight pesticides ranged from 8.5 to 9.5, with less than 50% of maximal activity expressed at pH 7.0. Maximal enzyme activity occurred at 35 C. The crude extract lost its activity at the rate of only 0.75%/day when stored at 6 C. Eight organic solvents, ranging from methanol to hexane, at low concentrations stimulated enzymatic hydrolysis by 3 to 20%, whereas at higher concentrations (1,000 mg/liter) they inhibited the reaction (9 to 50%). Parathion metabolites p-nitrophenol, hydroquinone, and diethylthiophosphoric acid, at up to 100-mg/liter concentrations, did not significantly influence enzyme activity.
一种从以有机磷杀虫剂对硫磷为生长底物的混合细菌培养物中提取的粗细胞提取物，在21℃下以每毫克蛋白质416纳摩尔/分钟的速率水解对硫磷。与0.1N氢氧化钠在40℃下的化学水解相比，这种酶促水解速率快2450倍。用这种酶制剂对12种常用有机磷杀虫剂中的8种进行酶促水解，速率范围为每毫克蛋白质12至1360纳摩尔/分钟。7种农药的水解速率明显高于化学水解（快40至1005倍）。这8种农药酶促水解的最适pH值范围为8.5至9.5，在pH 7.0时活性表达不到最大活性的50%。最大酶活性出现在35℃。粗提取物在6℃储存时，活性仅以每天0.75%的速率丧失。从甲醇到己烷的8种有机溶剂，在低浓度下可刺激酶促水解3%至20%，而在高浓度（1000毫克/升）时则抑制反应（9%至50%）。对硫磷代谢产物对硝基苯酚、对苯二酚和二乙基硫代磷酸，在浓度高达100毫克/升时，对酶活性没有显著影响。
