5β-CHOLESTANE-3α, 27-DIOL: NAD+ OXIDOREDUCTASE AND 3α-HYDROXY-5β-CHOLESTAN-27-AL: NAD+ OXIDOREDUCTASE IN RAT LIVER EXTRACT

Using rat liver alcohol:NAD+ oxidoreductase and aldehyde:NAD+ oxidoreductase, the following facts were found:　　1) 3α-hydroxy-5β-cholestan-27-al was reduced to 5β-cholestane-3α, 27-diol by liver alcohol: NAD+ oxidoreductase.　　2) The optimum pH was pH 7.0 with potassium phosphate buffer and pH 8.5 with Tris buffer.　　3) The Km value of the substrate to the enzyme was 14.3 μM.　　4) 3α-Hydroxy-5β-cholestan-27- al was oxidized to 3α-hydroxy-5β-cholestan-27-oic acid by liver aldehyde: NAD+ oxidoreductase.　　5) The optimum pH was pH 8.5 with Tris buffer.　　6) The Km value of the substrate to the enzyme was 26.3 μM.