Carbamate kinase of Lactobacillus buchneri NCDO110. I. Purification and properties.
Carbamate kinase has been prepared from Lactobacillus buchneri NCDO110. An approximately 91-fold increase in the specific activity of the enzyme was achieved. The purified extract exhibited a single band following polyacrylamide gel electrophoresis. The apparent molecular weight as determined by gel electrophoresis was about 97,000. The enzyme is stable for 2 weeks at -20 degrees C. Maximum enzymatic activity was observed at 30 degrees C and pH 5.4 in 0.1 M acetate buffer. L. buchneri carbamate kinase requires Mg2+ or Mn2+; its activity is higher with Mn2+. The activation energy of the reaction was 4078 cal mol-1 for the reaction with Mn2+ and 3059 cal mol-1 for the reaction with Mg2+. From a Dixon plot a pK value of 4.8 was calculated. The apparent Km values for ADP with Mg2+ or Mn2+ were 0.71 X 10(-3) and 1.17 X 10(-3) M, respectively, and the apparent Km values for carbamyl phosphate with Mg2+ or Mn2+ were 1.63 X 10(-3) and 1.53 X 10(-3) M, respectively. ATP and CTP acted as inhibitors of this reaction and the following values were obtained: Ki (ATP)Mg2+ = 9.4 mM, Ki (ATP)Mn2+ = 6.2 mM, and Ki (CTP)Mg2+ = 4.4 mM.
D002852:Chromatography, Ion Exchange; D003470:Culture Media; D004591:Electrophoresis, Polyacrylamide Gel; D006863:Hydrogen-Ion Concentration; D007778:Lactobacillus / Q000201:enzymology*; D008970:Molecular Weight; D010770:Phosphotransferases / Q000032:analysis / Q000302:isolation & purification*; D017851:Phosphotransferases (Carboxyl Group Acceptor)
D003470:Culture Media; D010770:Phosphotransferases; D017851:Phosphotransferases (Carboxyl Group Acceptor); C019288:carbamate kinase