The influence of lysis buffer composition on the expression and activity of protein tyrosine phosphatase

Lysis conditions are crucial in the extraction and solubilization of phosph otyrosine-containing proteins in a form that is immunoreactive, undegraded and enzymatically active. To establish optimal experimental conditions, we evaluated protein tyrosine phosphatase enzyme activity and the detection of PTP-1B protein in human acute promyelocytic leukaemic cells, both before a nd after retinoic acid treatment. We found that the composition of the lysi ng buffer greatly influenced the efficiency of solubilization, resulting in major alterations in the activity of protein tyrosine phosphatases and on the mobility of PTP-1B protein.