Characterization and Inhibitor Screening of Plateau Zokor Lactate Dehydrogenase C4

Lactate dehydrogenase C4 (LDH-C4) is considered to be a target protein for the development of contraceptives. In this work, the characterization of plateau zokor LDH-C4 and the screening of a series of N-substituted oxamic acids as inhibitors against zokor LDH-C4 were reported. The cDNA of zokor LDH-C gene was cloned and expressed in Escherichia coli, from which the protein was purified and further characterized. The protein was a tetramer (LDH-C4) and thermally stable up to 62 °C with a K m of 63.9 μM for pyruvate and with optimal pH values of 7.95 and 10.1 for the forward and backward reactions respectively. Virtual and in vitro screening against zokor LDH-C4 revealed eight N-substituted oxamic acids with IC50s ranging from 198 to 2513 μM, higher than that of oxamic acid (150 μM) and (ethylamino)(oxo)acetic acid (59 μM). The inhibition potencies of N-substituted oxamic acids tested are in the micromolar range, and the increase in the length of substituting chain seems not to increase inhibition potency.