GST fusion protein not cleaved by thrombin

[Mauro]

Hi everybody,
I hope somebody can help me....
I'm expressing a kinase in pGEX-2T vector. After purification on
glutathione beads my fusion protein has the right M.W.,
autophosphylation activity but I can't cleave it by thrombin at all. I
tried many different condition of thrombin concentration, temperature
and time with no success at all. Has anybody faced the same problem?
What to do?
I want to use it to produce antisera. Can I use it with the GST moiety
still attached?
.....any advice are welcome. Thanks

Mauro Rabino
Dep. of Biology
Hunter College
Rabino at genectr.hunter.cuny.edu