A novel membrane associated carbonyl reducing enzyme is present in smooth endoplasmic reticulum of mouse liver.
Evidence supporting the existence of two distinct carbonyl (metyrapone) reducing enzymes which differ in subcellular localization and immunological homology has been provided. A soluble enzyme, designated as carbonyl reductase (EC 1.1.1.184) is located in the cytosol. The distribution of the second, membrane associated, MPON-reductase shows an excellent linear correlation to NADPH-cytochrome c reductase and, on the other hand, is reciprocal to the RNA/protein ratio of submicrosomal preparations. This indicates that the membrane associated MPON-reductase is exclusively located in the smooth endoplasmic reticulum. Using antibodies against the purified membrane associated enzyme the extent of immunological crossreaction corresponds well to the specific activities of MPON-reductase in the granular fractions, thus further confirming the localization of this enzyme within this organelle. The absence of antigenic crossreaction to cytosolic MPON-reductase indicates differences also in terms of the immunological relationship between the two enzymes.
Ahlers
T
T
Department of Pharmacology and Toxicology, Philipps-University of Marburg, Germany.
Bode
H P
HP
Netter
K J
KJ
Maser
E
E
D000429:Alcohol Oxidoreductases / Q000302:isolation & purification / Q000378:metabolism*; D000449:Aldehyde Reductase; D000074408:Aldo-Keto Reductases; D000818:Animals; D002458:Cell Fractionation; D004591:Electrophoresis, Polyacrylamide Gel; D004721:Endoplasmic Reticulum / Q000201:enzymology*; D005260:Female; D008099:Liver / Q000201:enzymology*; D008797:Metyrapone / Q000494:pharmacology; D051379:Mice; D008815:Mice, Inbred Strains; D008970:Molecular Weight; D013347:Subcellular Fractions / Q000201:enzymology
D000429:Alcohol Oxidoreductases; D000074408:Aldo-Keto Reductases; C073803:metyrapone reductase; D000449:Aldehyde Reductase; C000614209:AKR7A5 protein, mouse; D008797:Metyrapone