I used your CNM kit isolating compartmental protein, and the protein concentration was measured by UV spectrum. The quantity of the membrane protein was 10 times more than the cytoplasmic protein, is this normal?
No, it is not normal. Usually the relative yield of Cytoplasmic and membrane fractions, it’s about 2-3:1. I would suggest you run your protein on SDS-PAGE gel and see if the protein intensity matched the concentration you have measured from UV spectrum. If the protein intensity from SDS-PAGE gel is consistent with the quantity measured from UV spectrum, then the tissues or the cells probably were not homogenized very well in the first step. Increasing the speed setting of the homogenizer for tissues, and increasing the repetition of homogenization up to 5 times (normally 3 times). will help. For cells, I suggest pipette enough times to make sure the cells are completely lysed.
