人体皮肤在胆红素光分解中的作用。

Role of human skin in the photodecomposition of bilirubin.

作者信息

Kapoor C L, Murti C R, Bajpai P C

出版信息

Biochem J. 1974 Sep;142(3):567-73. doi: 10.1042/bj1420567.

DOI:10.1042/bj1420567

PMID:4464841

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC1168320/

Abstract

Human skin epithelium and human skin were found to absorb both free bilirubin and serum-bound bilirubin from an aqueous buffered medium. The serum-bound bilirubin thus absorbed was readily released when human skin epithelium or human skin were transferred to media containing no bilirubin. 2. The K(m) values for serum-bound bilirubin were 1.8x10(-3)m and 2.2x10(-3)m respectively for human skin epithelium and human skin; corresponding K(m) values for free bilirubin were 3.0x10(-4)m and 5x10(-4)m. The V(max.) for bound and free bilirubin was of the same magnitude, the apparent V(max.) being 1.0 and 1.66mumol/g of tissue for human skin epithelium and human skin respectively. 3. When human skin that had acquired a yellow tinge by absorbing bilirubin was incubated in a buffered medium and exposed to a mercury-vapour light, the yellow colour disappeared and decomposition products of bilirubin accumulated in the medium. 4. Experiments with [(3)H]bilirubin indicated that the pigment absorbed by skin was photo-oxidized to products that were soluble in water and the quantity and number of such products increased with the time of exposure of human skin to the light-source. Under similar conditions [(3)H]bilirubin alone in buffered medium was also oxidized and gave products which by paper chromatography appeared to be different from those released by human skin that had absorbed bilirubin. 5. The results suggest that by virtue of its large surface area human skin can act as a matrix for the degradative action of light on bilirubin.

摘要

研究发现，人体皮肤上皮组织和人体皮肤能够从水性缓冲介质中吸收游离胆红素和血清结合胆红素。当将人体皮肤上皮组织或人体皮肤转移至不含胆红素的介质中时，所吸收的血清结合胆红素会很容易地释放出来。2. 人体皮肤上皮组织和人体皮肤对血清结合胆红素的米氏常数（K(m)）分别为1.8×10⁻³m和2.2×10⁻³m；游离胆红素的相应米氏常数为3.0×10⁻⁴m和5×10⁻⁴m。结合胆红素和游离胆红素的最大反应速度（V(max.)）大小相同，人体皮肤上皮组织和人体皮肤的表观最大反应速度分别为1.0和1.66μmol/g组织。3. 当通过吸收胆红素而呈现黄色的人体皮肤在缓冲介质中孵育并暴露于汞蒸气灯下时，黄色消失，胆红素的分解产物在介质中积累。4. 用[³H]胆红素进行的实验表明，皮肤吸收的色素被光氧化为可溶于水的产物，且这些产物的量和种类随着人体皮肤暴露于光源的时间增加而增加。在类似条件下，缓冲介质中单独的[³H]胆红素也被氧化，其产物通过纸色谱分析显示与吸收了胆红素的人体皮肤释放的产物不同。5. 结果表明，由于人体皮肤表面积大，它可以作为光对胆红素降解作用的基质。