期刊名称：Journal of Nutritional Science and Vitaminology
印刷版ISSN：0301-4800
电子版ISSN：1881-7742
出版年度：1976
卷号：22
期号：5
页码：389-396
DOI：10.3177/jnsv.22.389
出版社：Center for Academic Publications Japan
摘要：1. The tyrosinase reaction in the presence of a thiol compound was studied using mushroom tyrosinase (EC 1. 10. 3. 1) with regard to catechol-thiol conjugates. 2. Although tyrosine hydroxylation of tyrosinase was extremely decreased in the presence of a thiol compound, the inhibitory effect was removed by the addition of a pyrocatechol-cysteine conjugate, S-(2, 3-dihydroxyphenyl) cysteine, which was not oxidized by the enzyme. 3. The pyrocatechol-cysteine conjugate was also able to shorten the lag period of tyrosinase-dependent tyrosine hydroxylation. 4. The sigmoidal reaction curve of tyrosine hydroxylation observed in the presence of sulf hydryl compounds was found to be caused by the catechol-thiol conjugates, the final products of the enzyme reaction, which counteract the inhibitory effect of sulf hydryl compounds. 5. The pyrocatechol-cysteine conjugate, on the other hand, was shown to cause the decrease of the reaction rate of the enzyme during incubation.
