Production, purification and characterization of non-myristylated human T-cell protein tyrosine kinase in a baculovirus expression system.

A non-myristylated form (LCK M) of the human T-lymphocyte-specific protein tyrosine kinase (LCK) was produced at high levels in a baculovirus expression system (BVES) using two strategies. First, LCK M was produced by direct expression of a Gly2 --> Ala mutant of LCK. Second, LCK was produced as a glutathione S-transferase (GST) fusion, and LCK M was derived from the fusion protein by cleavage with thrombin. Both recombinant proteins (re-proteins) were produced at 5% of the total protein of infected Spodoptera frugiperda (Sf9) cells and were purified to >95% homogeneity. The enzymatic properties of the re-proteins and their inhibition by protein kinase inhibitors were comparable to the native enzyme (LCK N) derived from Jurkat cells and wild-type LCK derived from the BVES. The high production levels will facilitate the recovery of large quantities of re-protein for use in biochemical and biophysical studies.