Cysteine is the initial site of modification of α-crystallin by kynurenine
Cysteine is the initial site of modification of α-crystallin by kynurenine
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DOI：
10.1006/bbrc.2000.3461
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发表时间：
2000-09-16
影响因子：
3.1
通讯作者：
Truscott, RJW
中科院分区：
文献类型：
--
作者：
Aquilina, JA;Truscott, RJW
色氨酸代谢物（如犬尿氨酸）在中性pH下自发不稳定。它们发生侧链脱氨基反应，产生反应性α，β不饱和酮。在透镜中，这些化合物充当UV过滤剂，分解产物与透镜蛋白（晶体蛋白）的反应可能是该组织年龄依赖性着色的主要原因。在先前的研究中，其中高pH（pH 9）用于促进脱氨基和与透镜蛋白的缀合，发现组氨酸、赖氨酸和半胱氨酸残基被修饰。在这项研究中，我们表明，在pH 7，与主要的透镜伴侣α-晶状体蛋白的反应位点，是α A亚基的单个半胱氨酸残基，这种表观选择性具有重要的分支，因为半胱氨酸-犬尿氨酸加合物本身在生理条件下是不稳定的。(C)北京大学出版社.
Tryptophan metabolites, such as kynurenine, are spontaneously unstable at neutral pH. They undergo side-chain deamination yielding reactive alpha, beta unsaturated ketones, In the lens, where these compounds act as UV filters, reaction of the breakdown products with lens proteins (crystallins) may be largely responsible for age-dependent colouration of this tissue. In previous research, where high pH (pH 9) was used to promote deamination and conjugation with lens protein, histidine, lysine, and cysteine residues were found to be modified. In this study we show that, at pH 7, site of reaction with the major lens chaperone alpha-crystallin, is the single cysteine residue of the alpha A subunit, This apparent selectivity has important ramifications because the cysteine-kynurenine adduct is itself unstable under physiological conditions. (C) 2000 Academic Press.