Muralidharan V B, Kishimoto Y
J Biol Chem. 1984 Nov 10;259(21):13021-6.
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.
对高比活度的[1-¹⁴C]植烷酸在大鼠肝脏的核后及各种亚细胞组分中的α-氧化进行了研究。核后组分中的α-氧化需要ATP、Mg²⁺、烟酰胺和分子氧才能发挥活性。α-氧化受到铁特异性螯合剂和呼吸链抑制剂的抑制。一氧化碳的部分抑制表明细胞色素P-450可能参与其中。然而，经苯巴比妥处理的大鼠肝脏核后组分并未比对照更能刺激植烷酸的α-氧化。亚细胞分级分离表明，除线粒体组分外，胞质溶胶对于活性也是必需的。胞质因子似乎是可透析的；它经热处理会失活，但不受胰蛋白酶消化的影响。NAD、辅酶A、抗坏血酸和过氧化氢酶不能替代胞质活性，最近在脑羟化中鉴定出的热稳定因子（即腺苷核苷酸和谷氨酸）也不能替代。
