鸡蛋卵转铁蛋白过敏原的体外模拟消化特性

In Vitro Simulation of Digestive Characteristics of Ovotransferrin in Egg White

采用体外静态消化模式,分别模拟婴幼儿和成年人的胃液、小肠液以及小肠刷状缘膜酶消化鸡卵转铁蛋白,利用Tricine-SDS-PAGE和MALDI-TOF-MS对消化产物进行分析,研究鸡蛋蛋清过敏原卵转铁蛋白的消化特性。结果表明:婴幼儿和成年人的模拟胃液、小肠液以及小肠刷状缘膜酶都能够消化卵转铁蛋白。在模拟婴幼儿消化体系中,卵转铁蛋白胃消化产物分子质量范围为5~15 ku和30~50 ku,进一步经小肠消化后的产物分布在0.4~10 ku,最后经小肠刷状缘膜酶消化生成0.5~0.7 ku的肽段及部分5~13 ku的蛋白。卵转铁蛋白经模拟成年人胃消化的产物分子质量范围与模拟婴幼儿的一致,胃-小肠消化主要生成0.5~0.8 ku的肽段,再经小肠刷状缘膜酶消化后仍可生成0.5~0.7 ku的肽段。研究初步揭示卵转铁蛋白体外胃肠消化的规律,为卵转铁蛋白导致婴幼儿过敏提供部分试验依据。

Static digestion mode in vitro was used to digest egg ovotransferrin by the simulated gastric juice,small intestine fluid and small intestinal brush border membrane enzyme in infants and adults,respectively.Tricine-SDS-PAGE and MALDI-TOF-MS were used to analyze the digestion products at all stages to define the digestibility of ovotransferrin.It was shown that ovotransferrin could be digested by the simulated gastric juice,small intestine fluid and small intestinal brush border membrane enzyme in infants and adults.Regarding to the digestion in simulated gastrointestinal fluids in infants,the molecular weight of gastric digestion products were 5-15 ku and 30-50 ku.The small intestinal digestion products were 0.5-10 ku.At last,0.5-0.7 ku peptides were produced by small intestinal brush border membrane enzyme.The molecular weight of the digested ovotransferrin by the simulated gastric fluid in adult was the same as that of infants,while 0.5-0.8 ku peptides were mainly produced in intestinal digestion.However,only 0.5-0.7 ku peptides were generated after further digestion by small intestinal brush border membrane enzyme.This work preliminarily defined the characteristics of in vitro gastrointestinal digestion of ovotransferrin,providing some experimental support for better understanding that ovotransferrin is more likely to cause egg allergy in infants.