Carboxymethylhydroxymuconic semialdehyde dehydrogenase in the 4-hydroxyphenylacetate catabolic pathway of Escherichia coli.
5-Carboxymethyl-2-hydroxymuconic semialdehyde dehydrogenase in the 4-hydroxyphenylacetate meta-cleavage pathway has been purified to 96% homogeneity. The native enzyme, which appears to be a tetramer, has an apparent molecular weight of 210000. The purified enzyme shows a narrow pH optimum at pH 7.8 and does not require ions for its catalytic activity. Under standard assay conditions the enzyme acts preferentially with NAD but reduces NADP at 11% of the rate observed for NAD, primarily because of a difference in Km. Apparent Km values are 6.4 micro M for 5-carboxymethyl-2-hydroxymuconic semialdehyde and 52.2 micro M for NAD.
D000445:Aldehyde Oxidoreductases / Q000378:metabolism*; D004926:Escherichia coli / Q000201:enzymology*; D007700:Kinetics; D008970:Molecular Weight; D009243:NAD / Q000378:metabolism; D009249:NADP / Q000378:metabolism; D010648:Phenylacetates / Q000378:metabolism*
D010648:Phenylacetates; D009243:NAD; C008070:4-hydroxyphenylacetic acid; D009249:NADP; D000445:Aldehyde Oxidoreductases; C026251:5-carboxymethyl-2-hydroxymuconic acid semialdehyde dehydrogenase