title: Peptidase D of Escherichia coli K-12, a metallopeptidase of low substrate specificity.
abstract: Peptidase D of Escherichia coli was overproduced from a multicopy plasmid and purified to electrophoretic homogeneity. The pure enzyme was stable at 4 degrees C or -20 degrees C and had a pH optimum at pH 9, and a pI of 4.7; the temperature optimum was at 37 degrees C. As the enzyme was activated by Co2+ and Zn2+, and deactivated by metal chelators, it appears to be a metallopeptidase. By activity staining of native gels, 11 dipeptides which are preferentially cleaved by peptidase D were identified. Peptidase D activity required dipeptide substrates with an unblocked amino terminus and the amino group in the alpha or beta position. Non-protein amino acids and proline were not accepted in the C-terminal position, whereas some dipeptide amides and formyl amino acids were hydrolyzed. Km values of 2 to 5 mM indicate a relatively poor interaction of the enzyme with its substrates.
authors.affiliation: Universität Kaiserslautern, Abteilung Mikrobiologie, FRG.
authors.forename: U
authors.initials: U
authors.lastname: Schroeder
authors.forename: B
authors.initials: B
authors.lastname: Henrich
authors.forename: J
authors.initials: J
authors.lastname: Fink
authors.forename: R
authors.initials: R
authors.lastname: Plapp
mesh_terms: D004150:Dipeptidases / Q000302:isolation & purification* / Q000378:metabolism; D004789:Enzyme Activation; D004795:Enzyme Stability; D004926:Escherichia coli / Q000201:enzymology*; D006863:Hydrogen-Ion Concentration; D008666:Metalloendopeptidases / Q000302:isolation & purification* / Q000378:metabolism; D010957:Plasmids; D011994:Recombinant Proteins / Q000302:isolation & purification; D013379:Substrate Specificity; D013696:Temperature
chemical_list: D011994:Recombinant Proteins; D004150:Dipeptidases; C022449:proline dipeptidase; D008666:Metalloendopeptidases