there's a usual TCA protocol for yeast protein. I don't know if you followed a similar one, but summing up it basically consists on breaking the cells with glass beads and TCA, then adding more TCA to have a final concentration of 10% so it can precipitate when you centrifuge the sample and finally you resuspend the pellet in LB and correct pH with Tris base.
I have no idea abour other cell type protocol, but I think TCA is just used for yeast...