BIOCHEMICAL AND PHYLOGENETIC STUDIES OF CreD OF Corynebacterium glutamicum

摘要

CreD characterized as Mg2+-dependent phosphohydrolase with conserved HD domain was involved in 4-cresol metabolism in Corynebacterium glutamicum. Native molecular mass of 54 kDa suggested that the biological unit is a dimer. No deoxynucleotide triphosphate triphosphohydrolase (dNTPase) activity was detected for CreD. The apparent Km and Vmax values for 4-nitrophenyl phosphate were 0.35 mM and 16.23 ?M min-1 mg-1, respectively, while calculated values for kcat and kcat/Km were 0.4 s-1 and 1.14?103 M-1 s-1, respectively. Among thiol group inhibitors, iodoacetic acid significantly inhibited phosphohydrolase activity. Sequence identity and phylogenetic analysis suggested universal existence of CreD homologues. Involvement of HD-domain hydrolase in aromatic degradation has not been reported before.