Biosynthesis of a D-amino acid in peptide linkage by an enzyme from frog skin secretions
Biosynthesis of a D-amino acid in peptide linkage by an enzyme from frog skin secretions
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DOI：
10.1073/pnas.0500789102
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发表时间：
2005-03-22
影响因子：
11.1
通讯作者：
Kreil, G
中科院分区：
文献类型：
--
作者：
Jilek, A;Mollay, C;Kreil, G
D-氨基酸存在于来自两栖动物皮肤的一些肽中。这些残基衍生自相应前体中存在的相应L-氨基酸。从铃蟾的皮肤分泌物中，我们已经分离出一种酶，该酶催化模型肽的位置2中的L-Ile异构化为D-allo-Ile。在不添加辅因子的情况下进行的这一反应过程中，来自氚化水的放射性被掺入产物的第二位。该异构酶的氨基酸序列可以从克隆的cDNA和基因组DNA中推导出来。在非洲爪蟾卵母细胞中表达后，可检测到异构酶活性。与青蛙皮肤酶相关的多肽存在于包括人类在内的几种脊椎动物物种中。
D-amino acids are present in some peptides from amphibian skin. These residues are derived from the corresponding L-amino acids present in the respective precursors. From skin secretions of Bombinae, we have isolated an enzyme that catalyzes the isomerization of an L-Ile in position 2 of a model peptide to D-allo-Ile. In the course of this reaction, which proceeds without the addition of a cofactor, radioactivity from tritiated water is incorporated into the second position of the product. The amino acid sequence of this isomerase could be deduced from cloned cDNA and genomic DNA. After expression of this cDNA in oocytes of Xenopus laevis, isomerase activity could be detected. Polypeptides related to the frog skin enzyme are present in several vertebrate species, including humans.