Table 1. PTPase activity of GST-fusion proteins toward tyrosine-phosphorylated reduced and carboxymethylated-maleylated lysozyme and peptide DADEpYL
Specific activity, nmol/min per mg
Substrate GST-cytoPTPRQ GST-cytoPTPRQ(E2171D) GST-cytoPTP β
RCML 0.106 ± 0.05 0.916 ± 0.1 168 ± 15.4
DADEYL 0.029 ± 0.0 0.433 ± 0.05 229 ± 21.3
  • Activity of fusion proteins with indicated substrates are reported as means ± SD (n = 3). Fusion protein concentration was determined by absorbance at 280 nm and verified by the method of Bradford (Bio-Rad). RCML, reduced and carboxymethylated-maleylated lysozyme.