大豆分离蛋白的谷氨酰胺酶水解及其产物抗氧化性的研究

doi:10.13386/j.issn1002-0306.2012.24.050

大豆分离蛋白的谷氨酰胺酶水解及其产物抗氧化性的研究

Study on hydrolysis of soybean protein isolates by glutaminase and its impacts on antioxidant activity

摘要

摘要: 利用谷氨酰胺酶（EC3.2.1.5）对大豆分离蛋白进行限制性脱酰胺和水解处理,以SDS-PAGE及排阻色谱分析评价产物的蛋白质降解情况,并制备具有较低脱酰胺度的脱酰胺大豆分离蛋白产物。在大豆分离蛋白浓度5%（w/v）、谷氨酰胺酶添加量400U/kg酪蛋白、37℃的条件下分别反应12、24、36h,制得脱酰胺度分别为3.5%、5.6%、6.6%,水解度分别为0.9%、2.7%、3.5%的脱酰胺大豆分离蛋白。评价这3种脱酰胺大豆分离蛋白产物对Fe2+的螯合能力以及DPPH自由基的清除能力,结果表明,脱酰胺大豆分离蛋白产物对Fe2+的螯合能力以及对DPPH自由基的清除能力高于大豆分离蛋白,并随着脱酰胺度的增加而提高。

Abstract: Glutaminase (EC 3.2.1.5) was applied in the present work to treat soybean protein isolates (SPI) for deamidation and hydrolysis to a limited reaction extent. SDS-PAGE and size exclusion chromatography analysis were used to evaluate the degradation of SPI. Some deamidated SPI products with lower degree of deamidation were prepared with reaction conditions of SPI concentration of 5% (w/v) , glutaminase addition level of 400U/kg SPI, reaction temperature of 37℃ and reaction time were 12, 24 and 36h, respectively. Three deamidated SPI products prepared had the degree of deamidation of 3.5% , 5.6% and 6.6% , or degree of hydrolysis of 0.9%, 2.7% and 3.5%, respectively, were prepared. The iron (II) chelating activities and scavenging activity on DPPH radical of three deamidated SPI products were analyzed. The results indicated that the iron (II) chelating activities and scavenging activity on DPPH radical of three deamidated SPI products were higher than that of SPI, and would be enhanced as degree of deamidation increased.