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B6db references: 17616348

type Journal Article
authors Ranjith, N.K., Sasikala, Ch. and Ramana, Ch.V.
title Catabolism of L-phenylalanine and L-tyrosine by Rhodobacter sphaeroides OU5 occurs through 3,4-dihydroxyphenylalanine
journal Res Microbiol
sel selected
ui 17616348
year (2007)
volume 158
pages 506-511
keywords Eubacteria
abstract Rhodobacter sphaeroides OU5 utilized l-phenylalanine as sole source of nitrogen for growth. The metabolites of l-phenylalanine catabolism, i.e. 4-hydroxy phenylalanine (l-tyrosine), 3,4-dihydroxyphenylalanine (DOPA), 3,4-dihydroxyphenyl-pyruvic acid (DOPP), 3,4-dihydroxyphenyllactic acid (DOPLA), 3,4-dihydroxyphenyl-acetic acid (DOPAc) and 3,4-dihydroxybenzoic acid (PC), were identified using liquid chromatography-mass spectroscopy (LC-MS). With 2-oxoglutarate as an amino acceptor, DOPA aminotransferase activity was observed with cell-free extracts and the product DOPP was confirmed through mass analysis. Reductive deamination of DOPA also occurred in the absence of 2-oxoglutarate, whose products were 3,4-dihydroxyphenylpropionic acid (DPPA) and ammonia. The enzyme DOPA-reductive deaminase (DOPARDA) was purified to its homogeneity and characterized. DOPARDA has an obligate requirement for NADH and is functional at low concentrations of the substrate (<150 microM). The molecular mass of the purified enzyme was approximately 274kD and the enzyme could be a heterotetramer of 110, 82, 43 and 39kD subunits as determined by SDS-PAGE.
last changed 2007/11/30 13:16

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