TY - JOUR
T1 - Spectrophotometric and manometric studies of NADPH and NADH oxidase activities of rat liver microsomes
T2 - Effects of drugs and adenine nucleotides
AU - Gotto, A. M.
AU - Hutson, R. M.
AU - Meikle, A. W.
AU - Touster, Oscar
N1 - Funding Information:
* This study was supported in part by Public Health Service Grant AM-06859 from the National Institute of Arthritis and Metabolic Diseases and by Grant G-25126 from the National Science Foundation. t Aided by a Postdoctoral Research Scholarship from the American Cancer Society. 3 Medical student summer fellows supported by a grant from the National Institutes of Health. 0 The abbreviations used are: DCIP, 2,6-dichlorophenolindophenol; G6-P, glucose 6-phosphate; ADPR, adenosine diphosphate ribose; ADPR, adenosine diphosphate ribose; UDPG, uridine
Copyright:
Copyright 2017 Elsevier B.V., All rights reserved.
PY - 1965/6
Y1 - 1965/6
N2 - In view of the extensive interest in microsomal NADH and NADPH oxidases -for example, in the relationship of NADPH oxidase to drug-metabolizing enzymes-optimal conditions for the assay of these enzymes were established. Optimal pH was found to depend upon the buffer employed. Variation of microsomal concentration did not give strictly linear rates; high concentration of microsomes caused a decrease in observed reaction rate. In high concentration, both substrates were inhibitory. The reported ADP-stimulated oxidation of NADPH by rat liver microsomes could be confirmed only when particular reaction conditions were employed. The buffer used is crucial, and manometric and spectrophotometric assays may yield divergent results. Poor correlation was found between the extent of metabolism of drugs by NADPH-linked microsomal enzymes and the ability of the drugs to block the stimulation by ADP of oxygen uptake by microsomes in the presence of NADPH. This uptake has previously been suggested to involve the peroxidation of microsomal lipid.
AB - In view of the extensive interest in microsomal NADH and NADPH oxidases -for example, in the relationship of NADPH oxidase to drug-metabolizing enzymes-optimal conditions for the assay of these enzymes were established. Optimal pH was found to depend upon the buffer employed. Variation of microsomal concentration did not give strictly linear rates; high concentration of microsomes caused a decrease in observed reaction rate. In high concentration, both substrates were inhibitory. The reported ADP-stimulated oxidation of NADPH by rat liver microsomes could be confirmed only when particular reaction conditions were employed. The buffer used is crucial, and manometric and spectrophotometric assays may yield divergent results. Poor correlation was found between the extent of metabolism of drugs by NADPH-linked microsomal enzymes and the ability of the drugs to block the stimulation by ADP of oxygen uptake by microsomes in the presence of NADPH. This uptake has previously been suggested to involve the peroxidation of microsomal lipid.
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U2 - 10.1016/0006-2952(65)90251-0
DO - 10.1016/0006-2952(65)90251-0
M3 - Article
C2 - 4378660
AN - SCOPUS:50549201763
SN - 0006-2952
VL - 14
SP - 989
EP - 1002
JO - Biochemical pharmacology
JF - Biochemical pharmacology
IS - 6
ER -