in-vitro vs. in-vivo translation

[Weixing Luo]

Hello, netters:
 I have two questions regarding detection of a protein:
  1. Has anyone worked on a protein without Met?  I have used 35S-Cys to 
label the protein and it worked well by in vitro rabbit reticulocyte but 
not in transfected cells. 
  2.  If a protein is expressed by in vitro system, should it be 
expressed in cells in general?
  
  Any comments and suggestions will be appreciated.