An assay procedure for the vitamin K1 2,3-epoxide-reducing system of rat liver involving high-performance liquid chromatography.

since measurements of O2 uptake with intact bacteriaor extracts indicated approximately the same ratio of activities. Further, bacteria growing on D(-)-mandelate did not accumulate benzaldehyde, which shows that D(-)-mandelate dehydrogenase, rather than benzaldehyde dehydrogenase I (Cook et al., 1975), was now rate-limiting. D(-)-Mandelate dehydrogenase resembles L(+)-mandelate dehydrogenase in (a) its location in the membrane, (b) inhibition by oxalate, CNand EDTA and (c) range of electron acceptors. However, the new enzyme is less stable during storage, sonication or heating. L(+)-Mandelate dehydrogenase activity is not affected by D(-)-mandelate (Kennedy & Fewson, 1968a), but D(-)-mandelate dehydrogenase is inhibited by L(+)mandelate.