baterial grew on plates but not in liquid culture

[Wei Shao]

Hi, netters:

I am trying to express a viral protease in E.coli. The gene is cloned 
into pET24.  I transformed BL21 (DE3) with the contruct. The E.coli 
grew fine on plates with Kanamycine or Kanamycine plus glucose. But, 
when I tried to grow it in liquid medium with same kanamycine or 
kanamycine plus glucose. It did not grow. Then, I transformed 
DH5alpha with it. It grew fine. This seem suggest that the protein is 
toxic (it is a protease anyway).  What I do not understand is why 
transformed BL21 grew on plate, but not in liguid culture?  any 
suggestions?
Also, I am thinking to use Novagen's plys system to get tighter 
control. Any other suggestions?
Thanks in advance.
Please reply to:

Shaow at fcrfv1.ncifcrf.gov