High catalytic activity of alanine racemase from psychrophilic Bacillus psychrosaccharolyticus at high temperatures in the presence of pyridoxal 5'-phosphate.
We examined the effect of the pyridoxal 5'-phosphate (PLP) cofactor on the activity and stability of the psychrophilic alanine racemase, having a high catalytic activity at low temperature, from Bacillus psychrosaccharolyticus at high temperatures. The decrease in the enzyme activity at incubation temperatures over 40 degrees C was consistent with the decrease in the amount of bound PLP. Unfolding of the enzyme at temperatures above 40 degrees C was suppressed in the presence of PLP. In the presence of 0.125 mM PLP, the specific activity of the psychrophilic enzyme was higher than that of a thermophilic alanine racemase, having a high catalytic activity at high temperature, from Bacillus stearothermophilus even at 60 degrees C.
Okubo
Y
Y
Research Institute of Molecular Genetics, Kochi University, Nankoku, Kochi, Japan. okubo@rimg.kochi-u.ac.jp
Yokoigawa
K
K
Esaki
N
N
Soda
K
K
Misono
H
H
D000411:Alanine Racemase / Q000378:metabolism*; D001407:Bacillus / Q000201:enzymology*; D002384:Catalysis / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D011732:Pyridoxal Phosphate / Q000494:pharmacology*; D013696:Temperature
D011732:Pyridoxal Phosphate; D000411:Alanine Racemase