Do we need to deproteinize the sample before analyzing the cell lysate in NADP/NADPH (or NAD/NADH) assay?

No, the cell lysate can be used directly without deproteinization. Here is a sample protocol on how to prepare HL60 Cell Lysate for use in both NAD/NADH and NADP/NADPH assays:

1. 1 mL of HL 60 cells (1~2X10^6 cells/mL)
2. Centrifuge to remove medium
3. Add 200 μL lysis buffer to the cell pellet
4. Incubate 15 min at 37°C
5. Centrifuge 5 min to remove cell pellet
6. The supernatant can be used directly as the sample