畜牧兽医学报 ›› 2007, Vol. 38 ›› Issue (5): 471-475.doi:

• 动物营养 • 上一篇    下一篇

二肽在仔猪小肠刷状缘膜囊中跨膜转运的动力学特点研究

代建国;李德发;朴香淑;陈洪亮;潘宝海   

  1. 中国农业大学动物科技学院
  • 收稿日期:1900-01-01 修回日期:1900-01-01 出版日期:2007-05-25 发布日期:2007-05-25

Characteristics of Dipeptide Transport Kinetics in Small Intestinal Brush Border Membrane Vesicles of Piglets

DAI Jian-guo;LI De-fa; PIAO Xiang-shu;CHEN Hong-liang;PAN Bao-hai   

  1. College of Animal Science and Technology, China Agricultural University
  • Received:1900-01-01 Revised:1900-01-01 Online:2007-05-25 Published:2007-05-25

摘要: 为研究二肽在仔猪小肠刷状缘膜囊(Brush Border Membrane Vesicles, BBMV)中跨膜转运的动力学特点,采用同位素示踪及体外孵育技术,观察了几种不同条件下Gly-Pro的跨膜转运量。结果表明:(1)在有Na+和无Na+的条件下,Gly-Pro的转运均显著地受到Leu-Gly、Ala-His、Gly-Leu和His-Leu等二肽的显著抑制(P<0.01),但不受甘氨酸、L-丙氨酸、L-脯氨酸、L-亮氨酸、L-精氨酸、L-谷氨酰胺和L-蛋氨酸的影响;(2)仔猪小肠BBMV对Gly-Pro的转运呈现非线性关系,但是遵从Michaelis –Menten动力学方程,其Kt (亲合常数) 值为0.64 mmol/L,而Vmax为7.42 nmol/(min&#8226;mg)膜蛋白;(3)仔猪小肠BBMV对Gly-Pro的摄取是由于Gly-Pro直接进入BBMV内部的结果,而不是仅仅结合在BBMV上所引起。结果提示,Gly-Pro在仔猪小肠BBMV中的跨膜转运具有载体介导的转运特点。

Abstract: In order to study the characteristics of dipeptide transport kinetics in small intestinal brush border membrane vesicles (BBMV) of piglets, radioactive isotope trace and invitro incubation technique were used to observe the transmembrane transport of Gly-Pro under different condition. The results showed that: (1) Transport of Gly-Pro was inhibited (P < 0.01) by Leu-Gly, Ala-His, Gly-Leu, and His-Leu both in the presence and absence of a Na+ gradient, while not by Glycine, L-proline, L-leucine , L-arginine, L-glutamine and L-methionine; (2) The transport of Gly-Pro was nonlinear but followed by Michaelis –Menten kinetics. The kinetic constants suggested that the apparent Kt (affinity constant) value was 0.64 mmol/L, while Vmax was 7.42 nmol/ (min&#8226;mg)membrane protein; (3) The transport of Gly-Pro across the small intestinal BBMV of piglets was due to transport directly into the intravesicular space of BBMV rather than binding to vesicular membrane itself. It was suggested that transport of Gly-Pro in small intestinal BBMV of piglet posses characteristics of carrier-mediated transport.