Kinetic properties of glucose-6-phosphate dehydrogenase from lamb kidney cortex.
Glucose-6-phosphate dehydrogenase is the key regulatory enzyme of the pentose phosphate pathway and one of the products of this enzyme; NADPH has a critical role in the defence system against the free radicals. In this study, glucose-6-phosphate dehydrogenase from lamb kidney cortex kinetic properties is examined. The purification procedure is composed of two steps after ultracentrifugation for rapid and easy purification: 2', 5'-ADP Sepharose 4B affinity and DEAE Sepharose Fast Flow anion exchange chromatography. Previously, we used this procedure for the purification of glucose-6-phosphate dehydrogenase from bovine lens. The double reciprocal plots and product inhibition studies showed that the enzyme obeys 'Ordered Bi Bi' mechanism: K(m NADP+)K(m G-6-P) and K(i G-6-P) (dissociation constant of the enzyme--G-6-P complex) were found to be 0.018 +/- 0.002, 0.039 +/- 0.006 and 0.029 +/- 0.005 mM, respectively, by using nonlinear regression analysis. The enzyme was stable at 4 degrees C for a week.
Ulusu
Nuray N
NN
Faculty of Medicine, Department of Biochemistry, Hacettepe University, 06100 Ankara, Turkey. nnulusu@hacettepe.edu.tr
Tandogan
Berivan
B
Tezcan
Ferhan E
FE
D000818:Animals; D005954:Glucosephosphate Dehydrogenase / Q000737:chemistry* / Q000302:isolation & purification; D007672:Kidney Cortex / Q000201:enzymology*; D007700:Kinetics; D012756:Sheep
D005954:Glucosephosphate Dehydrogenase