Enzymatical properties of psychrophilic phosphatase I.
Phosphatase I purified from a psychrophile (Shewanella sp.) [Tsuruta et al. (1998) J. Biochem. 123, 219-225] dephosphorylated O-phospho-L-tyrosine and phospho-tyrosyl residues in phosphorylated poly(Glu4,Tyr1) random polymer (polyEY) and phosphorylated myelin basic protein (MBP) but not phosphoseryl and/or phosphothreonyl residues in phosphorylated histone H1, casein and phosphorylase a, indicating that the enzyme showed protein-tyrosine-phosphatase (PTPase, EC 3.1.3.48)-like activity in vitro. The enzyme was remarkably inhibited by diethylpyrocarbonate (DEPC), monoiodoacetic acid (MIAA), and monoiodoacetamide (MIAM). Binding of 1 mol of DEPC to 1 mol of the enzyme caused complete inhibition of the enzyme; and 0.88 mol of 1-carboxymethylated histidine per mole of the enzyme was found when 90% of enzyme activity was lost by modification with 14C-MIAA. These results indicated that this psychrophilic enzyme was a PTPase-like enzyme with histidine as its catalytic residue.
Tsuruta
H
H
Laboratory of Biological Chemistry, Department of Biofunctional Chemistry, Faculty of Agriculture, Kobe University, Nada-ku, Kobe, Hyogo, 657-8501, Japan.
Aizono
Y
Y
D000595:Amino Acid Sequence; D020134:Catalytic Domain; D003080:Cold Temperature; D004047:Diethyl Pyrocarbonate / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006092:Gram-Negative Facultatively Anaerobic Rods / Q000201:enzymology* / Q000235:genetics; D006639:Histidine / Q000737:chemistry; D007700:Kinetics; D008969:Molecular Sequence Data; D010744:Phosphoric Monoester Hydrolases / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism*; D017027:Protein Tyrosine Phosphatases / Q000378:metabolism; D013379:Substrate Specificity
D004791:Enzyme Inhibitors; D006639:Histidine; D010744:Phosphoric Monoester Hydrolases; D017027:Protein Tyrosine Phosphatases; D004047:Diethyl Pyrocarbonate