描述
4,8 dimethylnonanoyl carnitine is an intermediate in phytanic and pristanic acid metabolism. Both phytanic acid and pristanic acid are initially oxidized in peroxisomes to 4,8-dimethylnonanoyl-CoA, which is then converted to to 4,8-dimethylnonanoyl carnitine (presumably by peroxisomal carnitine octanoyltransferase), and exported to the mitochondrion. After transport across the mitochondrial membrane and transfer of the acylgroup to coenzyme A, further oxidation to 2,6-dimethylheptanoyl-CoA occurs (PMID: 9469587). 4,8 dimethylnonanoyl carnitine is not a substrate for carnitine acetyltransferase, another acyltransferase localized in peroxisomes, which catalyzes the formation of carnitine esters of the other products of pristanic acid beta-oxidation, namely acetyl-CoA and propionyl-CoA. (PMID: 10486279). Earlier studies have shown that pristanic acid undergoes three cycles of beta-oxidation in peroxisomes to produce 4,8-dimethylnonanoyl-CoA (DMN-CoA) which is then transported to the mitochondria for full oxidation to CO(2) and H(2)O. In principle, this can be done via two different mechanisms in which DMN-CoA is either converted into the corresponding carnitine ester or hydrolyzed to 4,8-dimethylnonanoic acid plus CoASH.(PMID: 11785945). Phytanic acid (3,7,11,15-tetramethylhexadecanoic acid) and pristanic acid (2,6,10,14-tetramethylpentadecanoic acid) are branched-chain fatty acids that are constituents of the human diet. As phytanic acid possesses a beta-methyl group, it cannot be degraded by beta-oxidation. Instead, phytanic acid is first degraded by alpha-oxidation, yielding pristanic acid, which is subsequently degraded by beta-oxidation. Phytanic acid alpha-oxidation is thought to occur partly, and pristanic acid beta-oxidation exclusively, in peroxisomes. Accumulation of phytanic acid and pristanic acid is found in blood and tissues of patients affected with generalized peroxisomal disorders. [HMDB]
InChI标识符
InChI=1S/C18H35NO4/c1-14(2)8-7-9-15(3)10-11-18(22)23-16(12-17(20)21)13-19(4,5)6/h14-16H,7-13H2,1-6H3