In vitro effects of some drugs on human erythrocyte glutathione reductase

摘要

The effects of ketotifen, meloxicam, phenyramidolHCl and gadopentetic acid on the enzyme activity of GR were studied using human erythrocyte glutathione reductase (GR) enzymes in vitro. The enzyme was purified 209-fold from human erythrocytes in a yield of 19% with 0.31U/mg. The purification procedure involved the preparation of haemolysate, ammonium sulphate precipitation, 2′′,5′-ADP Sepharose 4B affinity chromatography and Sephadex G-200 gel filtration chromatography. Purified enzyme was used in the in vitro studies. In the in vitro studies, IC 50 values and Ki constants were 0.012mM and 0.0008±0.00021mM for ketotifen; 0.029mM and 0.0061±0.00127mM for meloxicam; 0.99mM and 0.4340±0.0890mM for phenyramidolHCl; 138mM and 28.84±4.69mM for gadopentetic acid, respectively, showing the inhibition effects on the purified enzyme. PhenyramidolHCl showed competitive inhibition, whereas the others showed non-competitive inhibition.