You might try cleaving the proteins off the plasma membrane, then separating them from the cells, and analyzing the protein. Check out his paper:

Extracellular protease digestion to evaluate membrane protein cell surface localization

Richard N Besingi & Patricia L Clark

Nature Protocols, Volume 10, pp 2074–2080 (2015)

Dear Prof. John Carter, Thank you for your suggestion. I will see.

Trypsin alone cannot break open cells completely without using a lysis buffer. It is an enzyme that cuts proteins and is mainly used to detach cells from surfaces. However, it does not break the cell membrane, which is needed to release the contents inside the cells. Sometimes, if trypsin is used for too long or combined with other methods like shaking, it might damage the cells a little, but it won't fully lyse them. To fully break open cells, you need lysis buffers with detergents that can dissolve the membrane or other methods like sonication.