title: Purification and characterization of a plasmid-encoded aminoglycoside-(3)-N-acetyltransferase IV from Escherichia coli.
abstract: Plasmid-encoded aminoglycoside-(3)-N-acetyltransferase IV, AAC(3)-IV, was purified to homogeneity by affinity chromatography from E. coli. The enzyme was shown to consist of a monomer, with the apparent Mr being in agreement with that calculated from the nucleotide sequence of the aacC4 gene (Mr 28 500). Determination of the sequence of the N-terminal 6 amino acids revealed that processing did not occur, indicating the cytoplasmic localization of the AAC(3)-IV enzyme. A correlation of antibiotic resistance with Km values of the purified enzyme for a corresponding set of aminoglycoside substrates is discussed with respect to the mechanism of resistance in vivo.
mesh_terms: D000123:Acetyltransferases / Q000302:isolation & purification* / Q000378:metabolism; D000595:Amino Acid Sequence; D000617:Aminoglycosides / Q000378:metabolism; D002846:Chromatography, Affinity; D004352:Drug Resistance, Microbial; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics; D005839:Gentamicins / Q000494:pharmacology; D007700:Kinetics; D008970:Molecular Weight; D010446:Peptide Fragments / Q000302:isolation & purification; D011487:Protein Conformation; D011815:R Factors
chemical_list: D000617:Aminoglycosides; D005839:Gentamicins; D010446:Peptide Fragments; D000123:Acetyltransferases; C045539:aminoglycoside N(3')-acetyltransferase