Fig. 1.

Optimal pH of NAD degrading enzymes. The reaction mixture contained the following: substrate, NAD, 5 µmol; buffers of various pHs: 80 µmol (pH 3–6) citrate-buffer, (pH 6–9) Tris–acetate, (pH 9–10) carbonate–bicarbonate buffer; temp., 50 °C; protein extracts, 2.5 mg