Table 2. Analysis of Efficiency of pIR23-Catalyzed Reductive Amination for Substrates Where Spontaneous Imine Formation Was Quantitatively Observed vs Substrate Combinations Where Spontaneously Formed Imine Intermediates Were Undetectable^a.

^a[-] = not detected. 2 equiv amines a, c, f, and g and 4 equiv amines e and h were supplied for both enzymatic and nonenzymatic reactions. Reactions were run in 50 mM NaPi buffer, pH 7.5. All reactions were incubated for 6 h at 30 °C, 250 rpm shaking. Enzyme reaction contained C. ferrugineus reductive aminase (pIR23) 0.4mg mL^–1; B. subtilis glucose dehydrogenase (BsGDH) 0.2 mg mL^–1, NADP⁺. Only 0.5–15% alcohol product was detected.