ISSN:
1432-072X
Keywords:
Antibiotics
;
d-Amino acids
;
ld-Carboxypeptidase
;
Escherichia coli
;
Murein synthesis
;
Nocardicin A
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract A ld-carboxypeptidase from Escherichia coli K 12 was isolated by Tris-EDTA treatment and purified to electrophoretic homogeneity by DEAE-cellulose chromatography. The enzyme has a molecular weight of approximately 12,000 as determined by sodium dodecyl sulfatepolyacrylamide electrophoresis and by Sephadex G-100 gel filtration. The studies of the substrate specificity of the enzyme revealed that UDP-MurNAc-tetrapeptide is a superior substrate, with a K m value of 1×10-4 mol/l. The activity of the ld-carboxypeptidase was inhibited by d-amino acids and the β-lactam antibiotic nocardicin A. K i values of 0.3 and 43 mmol/l were determined for nocardicin A and d-homoserine, respectively. The properties of the purified enzyme correspond to activity I in ether treated cells.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00414732
