期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1992
卷号：89
期号：5
页码：1954-1957
DOI：10.1073/pnas.89.5.1954
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：The binding of oxidized phenolic compounds to proteins is of importance in a number of biological systems, including the sclerotization of insect cuticle and the tanning of cocoons. 3-Hydroxyanthranilic acid (3HAA), an aminophenol, is a tryptophan metabolite that undergoes autoxidation readily, and proteins incubated in the presence of 3HAA and oxygen become colored and oxidized. Some moth species are thought to employ this reactivity of 3HAA with proteins for the tanning of cocoons, but the detailed mechanism of this process has not been studied previously. We show that one reaction pathway involves the covalent coupling of 3HAA with tyrosine to form a benzocoumarin derivative, a dibenzo[b,d]pyran-6-one. The stability of the benzocoumarin to conditions of acid hydrolysis normally used for protein digestion has enabled the isolation of the tyrosine adduct from bovine serum albumin that had been incubated with 3HAA. The adduct was also isolated from cocoons of Samia cynthia and Hyalophora gloveri, two species of moths reported to utilize 3HAA for cocoon tanning. These findings indicate that one mechanism of interaction of 3HAA with proteins involves a radical-radical coupling with tyrosine residues.
