Staphylococcal L-asparaginase: enzyme kinetics.
The ph optimum of purified staphylococcal L-asparaginase (EC 3.5.1.1) was found to be between 8.6 and 8.8. The temperature optimum was 30 degrees-32 degrees C and the highest reaction rate occurred at 30 degrees C. The KM of the enzyme calculated from Lineweaver-Burk plot was 3.71 x 10(-2) M. Besides L-asparaginase, the substrate specificity of enzyme was restricted to N-alpha-acetyl-L-asparagine. D-asparagine, L-aspartic acid and D-glutamic acid were competitive inhibitors. Hg2+ and Cu2+ cations strongly inhibited the enzyme while Na+ and K+ cations strongly stimulated activity. Two SH-groups could be detected after enzyme denaturation with guanidine.
Sobiś
M
M
Department of Pharmaceutical Microbiology, Medical University, Lódź, Poland.
Mikucki
J
J
D001215:Asparaginase / Q000302:isolation & purification / Q000378:metabolism*; D001407:Bacillus / Q000201:enzymology; D004789:Enzyme Activation; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D009169:Mycobacterium tuberculosis / Q000201:enzymology; D011514:Proteus vulgaris / Q000201:enzymology; D013211:Staphylococcus aureus / Q000201:enzymology*; D013696:Temperature
D001215:Asparaginase