Phytanic acid alpha-oxidation in rat liver. Requirement of cytosolic factor.
The alpha-oxidation of [1-14C]phytanic acid of high specific activity was studied in postnuclear and various subcellular fractions from rat liver. alpha-Oxidation in the postnuclear fraction required ATP, Mg2+, nicotinamide, and molecular oxygen for activity. alpha-Oxidation was inhibited by iron-specific chelating agents and respiratory chain inhibitors. Partial inhibition by carbon monoxide indicated a possible involvement of cytochrome P-450. However, phenobarbital-treated rat liver postnuclear fraction did not stimulate phytanic acid alpha-oxidation above that of control. Subcellular fractionation indicated that in addition to the mitochondrial fraction, cytosol was required for activity. The cytosolic factor appeared to be dialyzable; it was inactivated by heat treatment, but not affected by trypsin digestion. NAD, CoA, ascorbic acid, and catalase did not replace cytosolic activity nor did the recently characterized heat-stable factors in brain hydroxylation, namely, adenosine nucleotides and glutamate.
D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D003505:Cyclodextrins / Q000494:pharmacology; D003600:Cytosol / Q000378:metabolism; D004537:Eicosanoic Acids / Q000378:metabolism*; D007700:Kinetics; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D008274:Magnesium / Q000494:pharmacology; D008297:Male; D008930:Mitochondria, Liver / Q000378:metabolism; D009536:Niacinamide / Q000494:pharmacology; D010084:Oxidation-Reduction; D010634:Phenobarbital / Q000494:pharmacology; D010831:Phytanic Acid / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D012710:Serum Albumin, Bovine / Q000494:pharmacology; D013347:Subcellular Fractions / Q000378:metabolism
D003505:Cyclodextrins; D004537:Eicosanoic Acids; D010831:Phytanic Acid; D009536:Niacinamide; D012710:Serum Albumin, Bovine; D000255:Adenosine Triphosphate; D008274:Magnesium; D010634:Phenobarbital