Carboxymethylhydroxymuconic semialdehyde dehydrogenase in the 4-hydroxyphenylacetate catabolic pathway of Escherichia coli

Biochim Biophys Acta. 1982 Oct 28;719(1):165-7. doi: 10.1016/0304-4165(82)90322-1.

Abstract

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.

MeSH terms

  • Aldehyde Oxidoreductases / metabolism*
  • Escherichia coli / enzymology*
  • Kinetics
  • Molecular Weight
  • NAD / metabolism
  • NADP / metabolism
  • Phenylacetates / metabolism*

Substances

  • Phenylacetates
  • NAD
  • 4-hydroxyphenylacetic acid
  • NADP
  • Aldehyde Oxidoreductases
  • 5-carboxymethyl-2-hydroxymuconic acid semialdehyde dehydrogenase