Would it be possible to do a protein extraction and perform a LC/MS proteomics analysis?

Sneha, Thanks for your reply. This way I think it may not be possible to distinguish between a defect in protein synthesis or protein degradation. Unless I am missing something?

At a general level, you could run a western blot, prior to- and after your drug treatment and stain the blots with Coomasie stain to see for a possible reduction or increase in global expression of proteins. Then, based on your target drug's downstream enzyme, you can look for specific expression of those proteins. 

It may be, that the standard radioactive assay may reveal more specific results. But one can do a quick western..

Hope it helps..

Thanks for your reply. This method again cannot identify whether the drug (with unknown targets) affected proteolysis, protein synthesis or mRNA stability and therefore requires further characterization of other systems.  

We have tested for global protein synthesis defects using westerns. A western blot tells if there is any reduction in overall or specific expression of protein. Because protein is isolated post-drug treatment. A western blot is also used for assessing protein degradation. For studying mRNA stability, you can try a qRT-PCR.