超滤膜分级玉米糖肽的抗氧化和乙醇脱氢酶激活活性

以玉米醇溶蛋白源玉米肽为研究对象，采用D-氨基葡萄糖和转谷氨酰胺酶对其进行酶法糖基化修饰制备玉米糖肽，然后利用截断分子质量为5、3和1 ku的超滤膜对玉米糖肽进行顺次分级分离，获得分子量>5、3~5、1~3和<1 ku四个组分。通过测定各组分的抗氧化和乙醇脱氢酶激活活性，表征分子量对玉米糖肽体外生物活性的影响。结果表明:清除DPPH自由基的玉米糖肽组分的分子量分布在1~5 ku范围内；螯合亚铁离子、清除超氧阴离子自由基、还原力和激活乙醇脱氢酶的玉米糖肽组分的分子量集中在1~3 ku范围内，在浓度为2 mg/mL时，相应的活力分别为83.22%、59.39%、2.248和37.92%；而分子量<5 ku的玉米糖肽组分均具有清除羟基自由基的活性，说明超滤膜分级对玉米糖肽的生物活性影响较大，可以依据玉米糖肽的生物活性选择超滤组分。

Antioxidant and Alcohol Dehydrogenase Activating Activities of Corn Glycopeptide by Ultrafiltration Membrane Classification

In the present work, corn peptides from zein were modified by D-glucosamine under transglutaminase to produce corn glycopeptides, and then the corn glycopeptides were fractionated sequentially using ultrafiltration membranes with molecular weight cut-off 5、3 and 1 ku, and four components with molecular weight >5, 3~5, 1~3 and <1 ku were obtained. The effect of molecular weight on the biological activities of corn glycopeptide was characterized by measuring the antioxidant and alcohol dehydrogenase activating activities of each molecular weight component. The results showed that the molecular weight distribution of the corn glycopeptides that had the ability to scavenge DPPH free radicals was in the range of 1~5 ku. At a concentration of 2 mg/mL, the corresponding activities were 83.22%, 59.39%, 2.248 and 37.92%, respectively. However, all corn glycopeptides components with molecular weight <5 ku had the activity of scavenging hydroxyl radicals, indicating that the biological activities of corn glycopeptides were greatly affected by the ultrafiltration membrane classification, and they could be selected according to the biological activities of corn glycopeptides.