Abstract
The L-(+) stereoisomer of β-monofluorolactic acid is a specific inhibitor of lactic acid dehydrogenase. The inhibition is competitive with respect to L-(+)-lactate, uncompetitive with DPN and pyruvate, and noncompetitive with DPNH. Kinetic analyses of substrate pairs in the presence of fluorolactate revealed that Ki with respect to DPN is a linear function of the concentration of lactate, while Ki with respect to lactate is directly proportional to the reciprocal of the concentration of DPN. In the reverse direction Ki with respect to pyruvate is independent of the concentration of DPNH, and Ki with respect to DPNH is a linear function of the reciprocal of the concentration of pyruvate. Fluorolactate in the forward reaction can combine only with the enzyme-DPN complex, while in the reverse direction the prerequisite for inhibition is the formation of an enzyme—pyruvate—DPNH complex.
ACKNOWLEDGMENTS Supported by grants of the National Science Foundation (GB 3488) and the U.S. Public Health Service (R01-CA-07955-01 and R01-HD-01239-09). The technical assistance of Mrs. Charlotte Schmid is gratefully acknowledged.
- Copyright ©, 1965, by Academic Press Inc.
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