Degradation of substituted mandelic acids by meta fission reactions.

A strain of Acinetobacter lwoffii degraded 4-hydroxymandelic and 4-hydroxy-3-methoxymandelic acids to their corresponding benzoates, which were then hydroxylated by specific monooxygenases to yield, respectively, protocatechuic and 3-O-methylgallic acids; these were substrates for meta fission dioxygenases. The product formed from 3-O-methylgallate underwent slow spontaneous cyclization at pH 7 to release methanol.

Properties of anthranilate hydroxylase (deaminating), a flavoprotein from Trichosporon cutaneum.

Anthranilate hydroxylase was purified from the yeast Trichosporon cutaneum. This enzyme is a simple flavoprotein which apparently does not require any additional cofactor for the conversion of anthranilate to 2,3-dihydroxybenzoate. Anthranilate hydroxylase has Mr of approximately 95,000, with subunit Mr of 50,000; it contains 2 mol of FAD/mol of enzyme.

Enzymology of the beta-ketoadipate pathway in Trichosporon cutaneum.

Cell extracts were prepared from Trichosporon cutaneum grown with phenol or p-cresol, and activities were assayed for enzymes catalyzing conversion of these two carbon sources into 3-ketoadipate (beta-ketoadipate) and 3-keto-4-methyladipate, respectively. When activities of each enzyme were expressed as a ratio, the rate for methyl-substituted substrate being divided by that for the unsubstituted substrate, it was apparent that p-cresol-grown cells elaborated pairs of enzymes for hydroxylation, dioxygenation, and delactonization. One enzyme of each pair was more active against its methyl-substituted substrate, and the other was more active against its unsubstituted substrate.

beta-Ketoadipate pathway in Trichosporon cutaneum modified for methyl-substituted metabolites.

Trichosporon cutaneum, when grown with p-cresol, catalyzed intradiol fission of the benzene nucleus of 4-methylcatechol before the complete catabolism of these two substrates. Steps in their conversion to pyruvate and acetyl coenzyme A were investigated by using cell extracts, and some properties of various new microbial catabolites are also described. These included (-)-2,5-dihydro-3-methyl-5-oxofuran-2-acetic acid (beta-methylmuconolactone) and (-)-3-keto-4-methyladipic acid and its coenzyme A ester; the latter was degraded by an enzymatic reaction sequence that included the coenzyme A esters of methylsuccinic, itaconic, and citramalic acids.