豚鼠小肠中的赖氨酸转运
Lysine transport in the guinea-pig small intestine.
作者信息
Munck B G
出版信息
Biochim Biophys Acta. 1984 Feb 29;770(1):29-34. doi: 10.1016/0005-2736(84)90069-5.
Interactions between cationic and neutral amino acids in transport across the brush-border membrane, Jmc, of the small intestine have been examined using preparations from the distal rabbit ileum and the rat and guinea-pig mid-small intestine. (1) In the guinea pig, the dependence of Jmc Lys on the concentration of lysine is best described in terms of two saturable transport mechanism in addition to free diffusion. (2) It is shown that the discrepancy between cis-effects of low concentrations of neutral amino acids on the Jmc of cationic amino acids, cis-stimulation in the guinea pig contra cis-inhibition in the rabbit and rat, represents species differences. In the guinea pig, imposing sodium-free conditions turns cis-stimulation into cis-inhibition. (3) It is demonstrated that in rat and guinea pig, leucine is transported both by the transport system(s) for cationic amino acids and by transport system(s) which cannot be inhibited by cationic amino acids.
利用来自兔回肠远端以及大鼠和豚鼠小肠中部的标本，对阳离子氨基酸和中性氨基酸在小肠刷状缘膜（Jmc）转运过程中的相互作用进行了研究。（1）在豚鼠中，除了自由扩散外，Jmc赖氨酸对赖氨酸浓度的依赖性最好用两种可饱和转运机制来描述。（2）结果表明，低浓度中性氨基酸对阳离子氨基酸Jmc的顺式效应存在差异，豚鼠中为顺式刺激，而兔和大鼠中为顺式抑制，这代表了种属差异。在豚鼠中，施加无钠条件会使顺式刺激转变为顺式抑制。（3）已证明，在大鼠和豚鼠中，亮氨酸既通过阳离子氨基酸转运系统进行转运，也通过不受阳离子氨基酸抑制的转运系统进行转运。
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