Vibrio mimicus arylesterase has thioesterase and chymotrypsin-like activity.
A Vibrio mimicus serine arylesterase and an Escherichia coli thioesterase/serine protease share 49.4% amino acid identity. The arylesterase has thioesterase activity for benzoyl-CoA and chymotrypsin-like activity for N-carbobenzoxy-L-phenylalanine p-nitrophenyl ester (NBPNPE). The gene encoding the V. mimicus enzyme is designated etpA. Substituting Ser31 of the V. mimicus enzyme with a glycine or an alanine altered its activity. In comparison with wild type enzyme, the S31A enzyme showed a 5-fold increase and 57% decrease in the catalytic efficiency for benzoyl-CoA and NBPNPE, respectively, and the S31G enzyme showed a 3.6-fold increase and 43% decrease in the catalytic efficiency for benzoyl-CoA and NBPNPE, respectively. For the two mutant enzymes an 8-fold decrease and a 6- to 7-fold increase in Km were seen for benzoyl-CoA and NBPNPE, respectively. The mutagenesis results prove that residue 31 plays an important role in the substrate-specificity.
Chang
R C
RC
Department of Sea-Food Technology, China Junior College of Marine Technology, Taipei, Taiwan.
Chen
J C
JC
Shaw
J F
JF
D000214:Acyl Coenzyme A / Q000378:metabolism; D000595:Amino Acid Sequence; D001483:Base Sequence; D002265:Carboxylic Ester Hydrolases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002918:Chymotrypsin / Q000378:metabolism*; D017124:Conserved Sequence; D004926:Escherichia coli / Q000201:enzymology; D007700:Kinetics; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D010170:Palmitoyl-CoA Hydrolase / Q000737:chemistry / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D017385:Sequence Homology; D012697:Serine Endopeptidases / Q000378:metabolism; D013329:Structure-Activity Relationship; D013379:Substrate Specificity; D014733:Vibrio / Q000201:enzymology*
D000214:Acyl Coenzyme A; D011994:Recombinant Proteins; C037817:benzoyl-coenzyme A; D002265:Carboxylic Ester Hydrolases; C019734:arylesterase; D010170:Palmitoyl-CoA Hydrolase; D012697:Serine Endopeptidases; D002918:Chymotrypsin