Contribution of peroxisomal beta-oxidation system to the chain-shortening of N-(alpha-methylbenzyl)azelaamic acid in rat liver.
Hepaptic peroxisomal and mitochondrial beta-oxidation of N-(alpha-methylbenzyl)azelaamic acid (C9), which is a possible metabolic intermediate of Melinamide, a potent hypocholesterolemic drug, were investigated. Isolated hepatocytes generated H2O2 when incubated with C9, indicating that C9 served as the substrate for peroxisomal beta-oxidation. Also with isolated peroxisomes a significant activity of peroxisomal beta-oxidation for C9-CoA measured by following cyanide-insensitive NAD reduction was observed, when the chain-shortened products such as C7 and C5 were detected from the incubation mixture of C9-CoA, and so NADH, acetyl-CoA and C2 units split off from C9-CoA were produced in stoichiometric amounts. In contrast, the mitochondrial beta-oxidation for C9 measured by following ketone body production and antimycin A-sensitive O2 consumption was not detectable, indicating that C9 is not metabolized by mitochondrial beta-oxidation. Comparative study of beta-oxidation capacities in peroxisomes and mitochondria indicate that the beta-oxidation of C9 occurs exclusively in peroxisomes. Also, the formation activity of C2 units liberated from C9 in intact hepatocytes reflects the peroxisomal beta-oxidation activity of liver homogenates with a highly close correlation. Therefore, it is concluded that C9 can be an excellent substrate for estimating peroxisomal beta-oxidation activity in intact cells.
Suzuki
H
H
Department of Clinical Biochemistry, Tokyo College of Pharmacy, Japan.
Mori
K
K
Yamada
J
J
Suga
T
T
D000818:Animals; D002478:Cells, Cultured; D044943:Fatty Acid Desaturases / Q000378:metabolism; D005227:Fatty Acids / Q000378:metabolism*; D008401:Gas Chromatography-Mass Spectrometry; D007700:Kinetics; D008297:Male; D008830:Microbodies / Q000201:enzymology / Q000378:metabolism*; D008930:Mitochondria, Liver / Q000201:enzymology / Q000378:metabolism*; D010084:Oxidation-Reduction; D010171:Palmitoyl Coenzyme A / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D013379:Substrate Specificity
D005227:Fatty Acids; C050451:N-(alpha-methylbenzyl)azelaamic acid; D010171:Palmitoyl Coenzyme A; D044943:Fatty Acid Desaturases