小麦面筋蛋白含半胱氨酸小麦肽的富集与表征

Enrichment and characterization of cysteine-containing peptides in wheat gluten protein

小麦面筋蛋白经过胃蛋白酶的处理产生有活性的含半胱氨酸小麦肽,半胱氨酸具有多种生理功能,已广泛应用于食品、医药和化妆品等领域。该文首先考察了还原处理对小麦面筋蛋白胃蛋白酶酶解物中含半胱氨酸小麦肽的影响。其次采用巯丙基树脂Sepharose 6B对含半胱氨酸小麦肽进行富集,巯基含量由原来的(195.10±12.79)μmol/g蛋白上升至(994.95±9.31)μmol/g蛋白,富集的肽组分中48.46%的肽段相对分子质量> 5 000 Da,而<1 000 Da小分子组分占比最少为7.93%,此外富集之后肽段的疏水性增大。利用单溴二胺对含半胱氨酸小麦肽进行荧光标记,标记之后的含半胱氨酸小麦肽相对分子质量在300~10 k Da,但相对分子质量<1 000 Da的组分中疏水性部分对荧光的贡献值大于其他组分。

Cysteine has been widely applied in many industries such as food,medicine and cosmetics because of their specific bioactivities.It is valuable to obtain active cysteine-containing peptides by enzymatic hydrolysis of cheap gluten protein.This study investigated the effect of reduction treatment on cysteine-containing wheat peptides from pepsine-derived hydrolysate,such as the SH content,molecular and hydrophobicity.Then,the cysteine-containing wheat peptides were enriched by mercaptopropyl resin Sepharose 6B and its content of SH increased from(195.10±12.79)μmol/g protein to(994.95±9.31)μmol/g protein.The molecular weights 5000 Da and below 1000 Da peptides in the cysteine-containing wheat accounted for 48.46%and 7.93%,respectively.Furthermore,the hydrophobicity of the peptide increased after enrichment.Moreover,monobromodiamine was used to label cysteine-containing peptides.After labeling,molecular weights of the peptides were distributed from 300 to 10 kDa.In contrast,the contribution of hydrophobic fractions with a molecular weight of less than 1000 Da was greater than that of other fractions.