中华稻蝗若虫不同龄期酯酶的特性

对中华稻蝗Oxya chinensis(Thunberg)1~4龄若虫的酯酶特性进行了比较研究。结果表明,不同龄期中华稻蝗的蛋白含量不同,随着龄期的增长,蛋白含量也随之增加,但各龄期增长的比例不同,2龄到3龄若虫蛋白含量增长的比例最大。不同龄期酯酶的总活力和比活力也不同,表现出相同的趋势,即随着龄期的增长,酯酶的总活力和比活力也随之增加,但在2龄到3龄期酯酶的活力增长最快。不同龄期酯酶动力学研究表明,不同龄期酯酶的Km值相近,无显著差异,Vmax值随着龄期的增长逐渐增大,这表明中华稻蝗若虫不同龄期酯酶活性的变化主要是量的变化,而非质的变异。中华稻蝗酯酶对3种底物亲和力的差异表明,-αNA是酯酶的最适底物。

Properties of esterase from different instars of Oxya chinensis nymphs

The properties of esterases from first to forth instar nymphs in the Chinese rice grasshopper,Oxya chinensis(Thunberg),were compared.The results showed that the protein concentrations increased with instars of O.chinensis nymphs,but the increasing ratios were different and the ratio from second to third instar nymphs was the fastest.The total and specific esterase activities increased with nymph instars, and the increasing ratio of esterase activities from second to third instar nymphs was also the fastest.The kinetic study of esterases from different instars showed that the K_m values were not significantly different and the V_(max) values increased as O.chinensis developed.It was inferred that the changes of esterase activities were quantitative rather than qualitative differences among the different instars.Among the three substrates tested,α_NA appeared to be the most favorable substrate for general esterases of O.chinensis according to their affinities to the esterases.