市售商品植酸酶的作用效果评定

Evaluation of the effectiveness of commercial phytases

在国标条件下比较了5种市售商品植酸酶(编号为A、B、C、D、E)的酶活力、最适pH、最适温度、酸碱耐受性、耐热性及蛋白酶耐受性,结果表明,A、B、D植酸酶的酶活力与标示值相近;A、B植酸酶在偏碱条件下具有相对高活性,C、D、E植酸酶在酸性与偏碱环境下均具有较高活力;A、B、C、D、E植酸酶最适温度在50～60℃之间;80℃热处理3 min后,A、B、E植酸酶的剩余酶活有80%以上,C、D植酸酶则仅剩余40%以下;经胃蛋白酶处理后,A、B、D、E植酸酶的剩余酶活50%以上,C植酸酶仅残余8%,而经胰蛋白酶处理后,C、D、E植酸酶剩余酶活70%以上。研究结果表明,5种商品植酸酶各有优点,但并不完全符合"理想"植酸酶的要求。

For the evaluation of the effectiveness of the commercial phytases （A, B, C, D, E） as feed additive, a series of in vitro experiments were carried out to determine the relative suitability, in vitro properties like temperature optimum, temperature stability, pH optimum and pH profile or proteolytie stability. The results showed that the enzyme activity of A, B, D had similar value; A, B in the partial alkaline conditions with relatively high activity, C, D, E in acidic and alkaline conditions were biased high vitality： the optimum temperature of A, B, C. D, E were between 50 - 60℃; After beating to 80℃ for 3 minutes. the residual activity of A. B. E were more than 80%, C, D only 40%; After exposure to pepsin, the phytases A , B, D, E were more than 50% residual activity. C is only 8% of the residual, and after treatment by trypsin, C, D, E were more than 70% residual activity. Five kinds of phytase goods has its own advantages, but it does not fully comply with the ＂ideal＂ requirements of pbytase.