Inhibition by analogues of L‐tyrosine transport by B16/F10 melanoma cells
作者:
J.,
Jara J.,
Martinez-Liarte F.,
期刊:
Melanoma Research
(OVID Available online 1991)
卷期:
Volume 1,
issue 1
页码: 15-22
ISSN:0960-8931
年代: 1991
出版商: OVID
关键词: Melanoma cells;L-tyrosine;amino acid uptake;tyrosine analogues;transport inhibition.
数据来源: OVID
摘要:
The effect of a number of L-tyrosine (L-Tyr) analogues on L-Tyr uptake by B16/F10 malignant melanocytes is reported. This amino acid can be taken up by two of the most ubiquitous transport systems found in animals cells, L and presumably ASC. L-Tyr analogues devoid of the amino group, likep-hydroxyphenyl pyruvic acid and related compounds, and L-Tyr analogues devoid of the carboxyl group, such as tyramine, do not affect L-Tyr uptake. The other aromatic amino acids, L-Phe and L-Trp, and the L-Tyr analogues DL-m-Tyr, L-diiodotyrosine and L-dopa, strongly inhibit the uptake of L-Tyr. This suggests that these chemicals are transported more efficiently than L-Tyr. The ASC system does not show stereospecificity, but the L system has greater affinity for L-Tyr than for D-Tyr. The ASC system also has greater affinity for tyrosine isomers with the hydroxyl group in theorthoandmetapositions. The presence of a methyl group at the α-carbon of L-Tyr and L-dopa also increases the affinity of the ASC system for these agents. In contrast, α-methylation decreases the affinity of the L system in comparison to L-Tyr. Finally, L-Tyr esters do not inhibit, but stimulate the transport of L-Tyr, mainly by the ASC system.
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