玉米六肽的酶法糖基化修饰对产物生物活性的影响

Effect of transglutaminase catalyzed glycosylation reaction on the biological activity of corn hexapeptide

以微生物转谷氨酰胺酶作为催化剂,D-氨基葡萄糖为酰基受体,通过糖基化反应修饰玉米六肽(Gln-Gln-Pro-Gln-Pro-Trp)制备玉米糖肽,对糖肽的部分生物活性进行测定,以表征糖基化修饰对玉米六肽生物活性的影响。实验结果表明,有一分子D-氨基葡萄糖与玉米六肽共价连接,且糖基化修饰改善了玉米六肽的抗氧化活性和乙醇脱氢酶激活率。其中,玉米糖肽清除DPPH自由基和ABTS自由基的半最大抑制浓度(EC_(50))值分别为1.04 mg/mL和0.80 mg/mL,分别比玉米六肽低0.25 mg/mL和0.10 mg/mL。在质量浓度为2.5 mg/mL时,糖肽的羟基自由基清除率、超氧阴离子自由基清除率、还原力、亚铁离子螯合率和乙醇脱氢酶激活率分别比玉米六肽高63.13%,16.29%,143.37%,100%和9.95%。

Microbial transglutaminase was applied as a biocatalyst and D-glucosamine as an acyl acceptor to modify corn hexapeptide(Gln-Gln-Pro-Gln-Pro-Trp)by glycosylation.Effect of galactosylated modification on corn hexapeptide bioactivity was evaluated by determining the antioxidant activities and alcohol dehydrogenase activation rate.The results showed that one molecule of D-glucosamine could be covalently conjugated to hexapeptide,and the antioxidant activity and alcohol dehydrogenase activation rate of corn hexapeptide were improved by glycosylation.The EC50 values for DPPH free radical and ABTS free radical of corn glycopeptide were 1.04 mg/ml and 0.80 mg/ml,respectively,which was 0.25 mg/ml and 0.10 mg/ml lower than that of corn hexapeptide,respectively.At the concentration of 2.5 mg/ml,the scavenging rate against hydroxyl free radical,the scavenging rate against superoxide anion free radical,reducing power,ferrous chelating capacity and the activation rate of alcohol dehydrogenase were increased 63.13%,16.29%,143.37%,100%and 9.95%over that of corn hexapeptide,respectively.