5-Carboxymethyl-2-hydroxymuconic semialdehyde dehydrogenases of Escherichia coli C and Klebsiella pneumoniae M5a1 show very high N-terminal sequence homology |
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Authors: | Tony Fawcett Amando Garrido-Pertierra Ronald A. Cooper |
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Affiliation: | Department of Biochemistry, University of Leicester, U.K. |
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Abstract: | 5-Carboxymethyl-2-hydroxymuconic semialdehyde (CHMS) dehydrogenase from Escherichia coli C and Klebsiella pneumoniae M5a1 have been purified and some of their properties studied. The apparent Km values for NAD and CHMS were 11.7 +/- 1.5 microM and 5.2 +/- 1.9 microM, respectively, for the K. pneumoniae enzyme, and 19.5 +/- 2.7 microM and 9.2 +/- 1.4 microM, respectively, for the E. coli enzyme. Both enzymes were optimally active at pH 7.5 in sodium phosphate buffer. They had subunit molecular weights of 52,000 (+/- 1000) and the native enzymes appeared to be dimers of identical subunits. The first 20 residues of their N-terminal amino acid sequences were 90% homologous. A degenerate oligonucleotide probe constructed to a six amino acid sequence common to both enzymes gave strong hybridization with DNA from E. coli strains B and W as well as with E. coli C and K. pneumoniae but little or no hybridization to DNA from E. coli K12 or Pseudomonas putida. |
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Keywords: | 4-Hydroxyphenylacetate catabolism Escherichia coli Klebsiella pneumoniae 5-Carboxymethyl-2-hydromuconic semialdehyde dehydrogenase N-terminal sequence |
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