|
The dual-specificity phosphatase is an emerging family of protein tyrosine phosphatase family , enabling the phosphorylation of tyrosine residues and serine / threonine residues dephosphorylation . During mitosis , signal transduction, cell extracellular stimuli and cell cycle pathways play an important role . Bispecific the phosphatase sLMWDSP ( low molecular weight the Dual specificity phosphatase , Staphylococcus aureus ) and protein phosphatase sPP2C ( protein from Staphylococcus aureus gene library cloned two new dual-specificity phosphatase , named low molecular weight phosphatase 2C, Staphylococcus aureus). sLMWDSP having 462 nucleotides, encoding a protein of 154 amino acids and having a dual-specificity phosphatase catalytic domain . The protein product of molecular weight of 18 kDa and an isoelectric point of 4.49 . sPP2C having 741 nucleotides, encoding a protein of 247 amino acids and having a phosphoprotein phosphatase 2C catalytic domain . Protein product of the molecular weight of 26.1 kDa and an isoelectric point of 4.95 . In E. coli . Rossetta the expression protein sLMWDSP , sPP2C . The high purity sLMWDSP , sPP2C was purified using affinity chromatography methods to obtain . the sLMWDSP and sPP2C phosphatase activity with p-nitrophenyl phosphate PNPP ( p - nitrophenyl phosphate , pNPP ) detection, found sLMWDSP optimum pH is 6.7, and the optimum temperature is 35 ° C , does not depend on the metal ions ; sPP2C the optimum pH is 11.0, and the optimum temperature is 37 ° C , and the activity of the enzyme must rely on a divalent metal ion, a divalent metal ion Mn 2 < / sup > the presence of the highest activity . The almost no inhibit General phosphatase inhibitor okadaic acid , EDTA sLMWDSP sodium vanadate can significantly inhibit the activity of the enzyme . sPP2C can inhibitor EDTA, sodium vanadate , sodium pyrophosphate , sodium phosphate, completely inhibited . Enzymology : the sLMWDSP and sPP2C the pSer / Thr and pTyr oligopeptide to dephosphorylation , to Description sLMWDSP and sPP2C of two new dual-specificity phosphatase .
|