培养的人成纤维细胞对甘氨酸的转运

Glycine transport by cultured human fibroblasts.

作者信息

Longo N, Franchi-Gazzola R, Bussolati O, Dall'Asta V, Nucci F A, Spisni A, Gazzola G C

机构信息

Istituto di Patologia Generale, Università di Parma, Italy.

出版信息

Biochem Biophys Res Commun. 1988 Apr 29;152(2):617-22. doi: 10.1016/s0006-291x(88)80083-4.

DOI:10.1016/s0006-291x(88)80083-4

PMID:3365244

Abstract

The transport of glycine was studied in cultured human fibroblasts. The amino acid entered the cell by Na+-dependent and Na+-independent mechanisms. Na+-independent glycine (0.1 mM) transport was less than 10% of total uptake and occurred by a mechanism formally indistinguishable from diffusion. Two distinct routes contributed to Na+-dependent glycine transport. The first route was identified with system A because it was inhibited by MeAIB and underwent adaptive regulation. The second route was identified with system ASC as it was inhibited by L-alanine, but not by MeAIB. Kinetic analysis revealed that the two systems operated glycine transport with the same Km of 1.6 mM, a value unusually high for system ASC.

摘要

在培养的人成纤维细胞中研究了甘氨酸的转运。氨基酸通过依赖钠离子和不依赖钠离子的机制进入细胞。不依赖钠离子的甘氨酸（0.1 mM）转运量不到总摄取量的10%，其发生机制与扩散在形式上无法区分。两种不同的途径促成了依赖钠离子的甘氨酸转运。第一条途径与A系统相关，因为它受到甲基氨基异丁酸（MeAIB）的抑制并经历适应性调节。第二条途径与ASC系统相关，因为它受到L-丙氨酸的抑制，但不受MeAIB的抑制。动力学分析表明，这两个系统以相同的1.6 mM米氏常数（Km）进行甘氨酸转运，这一数值对ASC系统来说异常高。