The photoreactions of 3,3',4',5-tetrachlorosalicylanilide anion (TCSA-) with two serum proteins were studied. TCSA- and anions of two similar compounds, N-ethyl-3,5-dichlorosalicylamide and salicylanilide, bind noncovalently to human serum albumin (HSA) without irradiation in aqueous pH 7.4 buffered solutions. TCSA- noncovalently bound to HSA yields three types of photoproducts when irradiated with ultraviolet light (lambda greater than 360 nm). A covalently bonded photoadduct between TCSA- and HSA is formed and histidines in HSA are chemically modified. In addition to these two types of photoproducts which involve HSA, two of the four TCSA- photoproducts which form when HSA is absent are also formed when the TCSA-/HSA complex is irradiated. The results presented indicate that not all proteins in the skin are capable of being the carrier protein in photoallergy of TCSA- and that cross reactivity to other halogenated salicylanilides can be explained by further photochemical reactions of TCSA- photoproducts.

中文翻译：

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3,3'，4'，5-四氯水杨基苯胺与蛋白质的光反应。

研究了3,3'，4'，5-四氯水杨基苯胺阴离子（TCSA-）与两种血清蛋白的光反应。TCSA和两种相似化合物（N-乙基-3,5-二氯水杨酰胺和水杨酰苯胺）的阴离子非共价结合到人血清白蛋白（HSA）上，而无需在pH 7.4的缓冲水溶液中进行辐照。当用紫外线（λ大于360 nm）照射时，与SAA非共价结合的TCSA会产生三种类型的光产物。在TCSA和HSA之间形成了共价键合的光加合物，并对HSA中的组氨酸进行了化学修饰。除了涉及HSA的这两种类型的光产物之外，当照射TCSA- / HSA络合物时，还会形成在不存在HSA时形成的四种TCSA-光产物中的两种。