谷朊粉水解物对微生物谷氨酰胺转胺酶稳定性的影响

Influence of wheat gluten partial hydrolysates on stability of aqueous microbial transglutaminase

为了比较几种多肽类物质对液体微生物谷氨酰胺酶(TGase)热稳定性的影响,利用复合蛋白酶FV酶解谷朊粉,制备了不同水解程度的谷朊粉水解物(WGPHs),并对添加了WGPHs的TGase热稳定性进行了分析。结果表明,添加一定量的谷朊粉水解物能明显提高谷氨酰胺转胺酶的热稳定性,而水解植物蛋白、蛋白胨的添加对TGase的热稳定性无影响,大豆低聚肽甚至降低了TGase的热稳定性;复合蛋白酶FV水解谷朊粉过程中所产生的水解物-小麦肽具有抗氧化能力;添加水解时间为20 min的谷朊粉水解物到TGase液中,50℃处理2 h后,其酶活残存率为95.90%,较对照高30.90%,但随着水解的进行,谷朊粉水解物对提高TGase热稳定性的作用减小,甚至降低了TGase的热稳定性。由此可见,以谷朊粉水解物作为保护剂,在添加量相同的条件下,水解20 min时的谷朊粉水解物保护效果更佳。

The influence of different polypeptides on thermal stability of microbial transglutaminase was investigated in the study,Bioprotease FV-assited hydrolysates of wheat gluten with different degree of hydrolysis （DH） was prepared and the variety of themal stability of TGase added by WGPHs was analyzed. The results showed that the thermal stability of TGase was improved by wheat gluten partial hydrol-ysates（WGPHs） ,but decreased by the soybean oligo-peptide, and the addition of hydrolyzed vegetable protein or peptone had no effect on the thermal stability of TGase; bioprotease FV-assited hydrolysates of wheat gluten showed the antioxidative capacity. Enzyme activity of the TGase remained at 95.90% after heating at 50 ℃ for 2 hours when the 20 min hydrolysates had been added, 30.90% higher than the control. But the improving effect of WGPHs on thermal stability of TGase decreased with the increase of DH. So,the 20 min WGPHs had the best protective effect when added with the same quantity.