title: In vitro effects of some drugs on human erythrocyte glutathione reductase.
abstract: The effects of ketotifen, meloxicam, phenyramidol-HCl 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 0.31 U/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 K(i) constants were 0.012 mM and 0.0008 ± 0.00021 mM for ketotifen; 0.029 mM and 0.0061 ± 0.00127 mM for meloxicam; 0.99 mM and 0.4340 ± 0.0890 mM for phenyramidol-HCl; 138 mM and 28.84 ± 4.69 mM for gadopentetic acid, respectively, showing the inhibition effects on the purified enzyme. Phenyramidol-HCl showed competitive inhibition, whereas the others showed non-competitive inhibition.
authors: Department of Chemistry, Science Faculty, Ataturk University, Erzurum, Turkey.
authors: Muhammet
authors: M
authors: Karaman
authors: Ebru
authors: E
authors: Akkemik
authors: Harun
authors: H
authors: Budak
authors: Mehmet
authors: M
authors: Ciftci
mesh_terms: D004305:Dose-Response Relationship, Drug; D004912:Erythrocytes / Q000201:enzymology*; D019786:Gadolinium DTPA / Q000494:pharmacology*; D005980:Glutathione Reductase / Q000037:antagonists & inhibitors* / Q000302:isolation & purification / Q000378:metabolism*; D006801:Humans; D007665:Ketotifen / Q000494:pharmacology*; D000077239:Meloxicam; D011725:Pyridines / Q000494:pharmacology*; D013329:Structure-Activity Relationship; D013843:Thiazines / Q000494:pharmacology*; D013844:Thiazoles / Q000494:pharmacology*
chemical_list: D011725:Pyridines; D013843:Thiazines; D013844:Thiazoles; D005980:Glutathione Reductase; D019786:Gadolinium DTPA; C478450:phenyramidol; D000077239:Meloxicam; D007665:Ketotifen