谷氨酰胺和丙氨酸向大鼠结肠细胞的转运。
The transport of glutamine and alanine into rat colonocytes.
作者信息
Ardawi M S
出版信息
Biochem J. 1986 Aug 15;238(1):131-5. doi: 10.1042/bj2380131.
The transport of glutamine and alanine into isolated rat colonocytes was studied. The transport of both amino acids appears to be dependent on a Na+ gradient. The apparent Km values for the transport of glutamine and alanine were 2.56 +/- 0.84 and 5.35 +/- 1.20 mM respectively, but with similar Vmax. values. Glutamine and alanine transport were mutually competitive, and the transport of both amino acids was competitively inhibited by 2-methylaminoisobutyrate. In contrast, histidine inhibited the transport of both glutamine and alanine non-competitively. It is concluded that glutamine and alanine are transported into rat colonocytes by a common carrier system similar to System A of other cells. It is suggested that the metabolic function of this transport system in rat colonocytes might be the partial exchange of extracellular glutamine for intracellular alanine.
对谷氨酰胺和丙氨酸进入分离的大鼠结肠细胞的转运进行了研究。这两种氨基酸的转运似乎都依赖于Na+梯度。谷氨酰胺和丙氨酸转运的表观Km值分别为2.56±0.84和5.35±1.20 mM，但Vmax值相似。谷氨酰胺和丙氨酸的转运相互竞争，且两种氨基酸的转运均受到2-甲基氨基异丁酸的竞争性抑制。相反，组氨酸非竞争性地抑制谷氨酰胺和丙氨酸的转运。结论是，谷氨酰胺和丙氨酸通过与其他细胞的A系统类似的共同载体系统转运到大鼠结肠细胞中。有人提出，该转运系统在大鼠结肠细胞中的代谢功能可能是细胞外谷氨酰胺与细胞内丙氨酸的部分交换。
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