Metabolic characterisation of a novel vanillylmandelate-degrading bacterium.
A newly isolated gram-negative bacterium, possibly Brevundimonas diminuta, utilised D,L-vanillylmandelate (D,L-VMA) as a sole carbon and energy source. The organism converted D,L-VMA to vanillylglyoxylate using a soluble NAD-dependent dehydrogenase specific for D-VMA and a dye-linked, membrane-associated L-VMA dehydrogenase. Vanillylglyoxylate was further metabolised by decarboxylation, dehydrogenation and demethylation to protocatechuate. A 4,5-dioxygenase cleaved protocatechuate to 2-hydroxy-4-carboxymuconic semialdehyde. Partially purified d-VMA dehydrogenase exhibited optimal activity at 30 degrees C and pH 9.5 and had an apparent Km for D-VMA of 470 microM. Although induced by several substituted mandelates, the enzyme had a narrow substrate specificity range with virtually no activity towards D-mandelate. Such properties render the enzyme of potential use in both diagnostic and biosynthetic applications.
Turner
J E
JE
Microbial Antigens Department, Centre for Applied Microbiology & Research, Porton Down, Salisbury, Wiltshire SP4 OJG, UK.
Allison
N
N
Fewson
C A
CA
D001419:Bacteria / Q000201:enzymology* / Q000378:metabolism; D002262:Carboxy-Lyases / Q000032:analysis / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial / Q000235:genetics; D006899:Mixed Function Oxygenases / Q000032:analysis / Q000378:metabolism; D008956:Models, Chemical; D015394:Molecular Structure; D009243:NAD / Q000378:metabolism; D010088:Oxidoreductases / Q000302:isolation & purification* / Q000378:metabolism; D010105:Oxygenases / Q000032:analysis / Q000378:metabolism; D014642:Vanilmandelic Acid / Q000378:metabolism*
D009243:NAD; D014642:Vanilmandelic Acid; D006899:Mixed Function Oxygenases; D010088:Oxidoreductases; D010105:Oxygenases; D002262:Carboxy-Lyases