The Influence of some Anti-pyretic and Anti-inflammatory Drugs on the Activity of Lactate Dehydrogenase ; Kinetic Study.

Abstract


Lactate dehydrogenase (LDH) is an enzyme EC (1. 1.1.27) that functions in anaerobic glucose metabolism and glucose synthesis (1). LDH is present in a wide variety of organisms including plants and animals (2). LDH has known effectors like lactate , pyruvate, NAD+, NADH, pH, buffers composition, ionic strength(4), fructose 1,6 bisphosphate, divalent cations such as Mn2+ or Co2+ (5). Proline and trimethylamine oxid (2µ) also affect the activity of LDH(6). Drugs like antipyretic and anti-inflammatory were reported to affect lactate dehyydrogenase activity (7,8).
In this study we study the effect of some antipyretic drugs ( aspegic, paracetamol, diclofenac) and anti-inflammatory drugs( hydrocortisone) on the activity of LDH and the result reveled that aspegic and paracetamol increased the activity of LDH for 2-folds,diclofenac for 1-fold and hydrocortisone for 1.8-fold, and only the actiavation in the presence of paracetamol was concentration dependant.
The measurement of kinetic parameter reveled that LDH do not obeys Mechelis-Menten equation. Aspegic and paracetamol increased the km values at approximant low conc. of pyruvate and decreases the km values for approximant 10- fold at high conc. of pyruvate , while diclofenac increases the km values at all conc. of pyruvate .On the other hand hydrocortisone at as a moderate activator for LDH. This difference in the effect of these drugs on the activity of LDH could be due to the difference in the polarity of the drugs.

Key word: lactate dehydrogenase, LDH, aspegic, paracetamol, diclofenac, hydrocortisone ,inhibitor ,activator .