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  

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

作　　者：代建国[1] 李德发[1] 朴香淑[1] 陈洪亮[1] 潘宝海[1] 

机构地区：[1]中国农业大学动物科技学院,北京100094

出　　处：《畜牧兽医学报》2007年第5期471-475,共5页ACTA VETERINARIA ET ZOOTECHNICA SINICA

基　　金：国家自然科学基金项目(39870583)

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的转运均受到Leu-Gly、Ala-His、Gly-Leu和His-Leu等二肽的极显著抑制(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.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上所引起的。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。In order to study the characteristics of dipeptide transport kinetics in small intestinal brush border membrane vesicles （BBMV） of piglets, radioactive isotope trace and in vitro 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 significantly （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 · 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.

关 键 词：二肽 仔猪 刷状缘膜囊 转运动力学 

分 类 号：Q67[生物学—生物物理学]