Comparative tyrosine degradation in Vibrio cholerae strains. The strain ATCC 14035 as a prokaryotic melanogenic model of homogentisate-releasing cell.
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| Abstract |
The relationship between L-tyrosine catabolism and melanin formation was studied in the Vibrio cholerae strains ATCC 14035 and CECT 557. It is shown that both strains degrade L-tyrosine by the same pathway as eukaryotic cells, giving homogentisate as intermediate. ATCC 14035, an O1 strain, which is not able to grow using L-tyrosine as sole carbon and energy source, but it forms pyomelanin from homogentisate. The second strain, which is non-O1, is able to grow using L-tyrosine as sole carbon and energy source, but it does not form any pigment. Both strains contain all the enzymes involved in the L-tyrosine catabolism. The three late enzymes of the pathway, homogentisate oxygenase, maleylacetoacetate isomerase and fumarylacetoacetate hydrolase, are induced by L-tyrosine, but the degree of induction is much lower in the ATCC 14035 strain. Thus, the distal part of the pathway becomes the rate-limiting steps in the L-tyrosine catabolism, explaining homogentisate accumulation and pyomelanogenesis in this strain. It is proposed that V. cholerae might be a useful prokaryotic model to show that alkaptonuria and other diseases related to L-tyrosine metabolism could occur in animals even when no particular enzyme involved in that pathway is lacking.
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| Authors | A Sanchez-Amat, C Ruzafa, F Solano |
| Journal | Comparative biochemistry and physiology. Part B, Biochemistry & molecular biology (Comp Biochem Physiol B Biochem Mol Biol) Vol. 119 Issue 3 Pg. 557-62 (Mar 1998) ISSN: 1096-4959 [Print] England |
| PMID | 9734339 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't) |
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