Catalytic efficiency and some structural properties of cold-active protein-tyrosine-phosphatase.
A procedure was established for expression and purification of abundant recombinant cold-active protein-tyrosine-phosphatase (RCPTPase), which showed identical enzymatic characteristics to the native enzyme (NCPTPase). The purified RCPTPase showed high catalytic activity at low temperature and maximal activity at 30 degrees C. RCPTPase has a thermodynamic characteristic in that its activation enthalpy was determined to be low, 4.3 kcal/mol, at temperatures below 19.3 degrees C, where the Arrhenius relationship exhibited an inflection point, in comparison with 20.3 kcal/mol above 19.3 degrees C. Also, the thermostability, DeltaG(water), of the catalytic site in the RCPTPase molecule was increased with a decrease in temperature. It was considered that cold-active protein-tyrosine-phosphatase could maintain its catalytic site in a stable conformation for eliciting high catalytic activity with low activation enthalpy at low temperature.
Tsuruta
Hiroki
H
Laboratory of Biological Chemistry, Department of Biofunctional Chemistry, Faculty of Agriculture, Kobe University, Nada-ku, Kobe, Hyogo 657-8501, Japan.
Aizono
Yasuo
Y
D002384:Catalysis; D020134:Catalytic Domain; D003080:Cold Temperature; D007700:Kinetics; D011487:Protein Conformation; D017027:Protein Tyrosine Phosphatases / Q000737:chemistry* / Q000378:metabolism; D020592:Shewanella / Q000201:enzymology; D013816:Thermodynamics
D017027:Protein Tyrosine Phosphatases