Gly-Gly肽和Gly-L-Leu肽在蛋鸡肠道内水解的研究

Study on Hydrolysis of Gly-Gly and Gly-L-Leu of Intestinal Peptidase

采用蛋鸡离体外翻肠段培养法,将小肠分为十二指肠、空肠前段、中段、后段和回肠五个部位肠段,洗净外翻。2种二肽培养液(Gly-Gly肽和Gly-L-Leu肽溶液)作为两组对照培养液,每种二肽培养液中添加肽酶抑制剂(Bestatin和Amastatin),作为试验培养液,39.5℃培养25min,每5min取样一次,测定培养液中的二肽含量。结果表明,培养5min后,含Gly-Gly肽的对照和试验培养液中均未能检测到完整Gly-Gly肽。而含Gly-L-Leu肽的对照培养液Gly-L-Leu肽的含量降低到16.75％,试验培养液则下降到43.40％。而试验培养液中Gly-L-Leu肽的含量10min后无显著降低(P>0.05)。各培养时段试验培养液Gly-L-Leu含量均显著高于对照培养液(P<0.05)。由此认为,离体肠囊在培养过程中能够迅速释放肠肽酶及一些生物活性物质,快速水解2种二肽。肽酶抑制剂(Bestatin和Amastatin)能抑制Gly-L-Leu的水解,但不能抑制Gly-Gly的水解。

This study based on culturing small intestine segments of laying hen in vitro:Small intestine was separated into five segments:duodenum,proximal jejunum,middle jejunum,distal jejunum and ileum.Each intestine segment are about 5 cm. Peptidase inhibitor(Bestatin and Amastin)was used;20mmol/L Gly-Gly and Gly-L-Leu as control,and each kind's dipeptide solution was treated with inhibitor as test group.Culture at 39.5℃ for 25 min and sample was taken every 5 min and measured dipeptide content in incubation medium by HPLGGly-Gly couldn't be detected in both groups and control group after 5 min; Gly-L-Leu content in test group decreased to 43.40%, but in control group decreased to 16.75%;in test group Gly-L-Leu content was slightly different(P>0.05) from 10 min to 25 min,about 8mmol/L;Total content of Gly-L-Leu was significantly different between test group and control one(P<0.05).These findings explained: intestinal peptidase was released quickly into the culture medium and hydrolyzed dipeptide. Bestatin and Amastatin could inhibit the hydrolysis of Gly-L-Leu,but not to Gly-Gly.