Pande S V, Murthy M S, Noël H
Biochim Biophys Acta. 1986 Jun 27;877(2):223-30. doi: 10.1016/0005-2760(86)90298-5.
Rates of carnitine palmitoyltransferase-catalyzed conversion of palmitoylcarnitine to palmitoyl-CoA are markedly decreased with the progress of this reaction presumably owing to the build up of inhibitory palmitoyl-CoA in the enzyme vicinity. High, above micellar, concentrations of palmitoylcarnitine, phosphatidylcholine liposomes and high KCl concentrations increased the activity, apparently by facilitating the removal of palmitoyl-CoA from the enzyme surface. The presence of cardiolipin was found to be inhibitory. The enzyme activity followed in the direction of palmitoylcarnitine formation with low palmitoyl-CoA concentration as substrate, was inhibited by phosphatidylcholine, but stimulated by cardiolipin. Both of these lipids markedly stimulated the enzyme activity followed by the isotope exchange procedure which requires progression of both the forward and the backward reactions. The results indicate that one of the effects of phospholipids on carnitine palmitoyltransferase activity is exerted from the ability of these substances to bind the amphipathic reactants of this enzyme, particularly long-chain acyl-CoA. The possibility that the activity of the membrane-bound carnitine palmitoyltransferase may at times be affected by changes in the concentrations and composition of the various phospholipids in the enzyme's vicinity is raised by these findings.
随着该反应的进行，肉碱棕榈酰转移酶催化棕榈酰肉碱转化为棕榈酰辅酶A的速率显著降低，这可能是由于酶附近抑制性棕榈酰辅酶A的积累所致。高于胶束浓度的高浓度棕榈酰肉碱、磷脂酰胆碱脂质体和高氯化钾浓度可提高活性，显然是通过促进棕榈酰辅酶A从酶表面的去除。发现心磷脂具有抑制作用。以低浓度棕榈酰辅酶A为底物时，酶活性沿棕榈酰肉碱形成的方向进行，受到磷脂酰胆碱的抑制，但受到心磷脂的刺激。这两种脂质都显著刺激了通过同位素交换程序测定的酶活性，该程序需要正向和反向反应的进行。结果表明，磷脂对肉碱棕榈酰转移酶活性的影响之一源于这些物质结合该酶两亲性反应物，特别是长链酰基辅酶A的能力。这些发现提出了膜结合肉碱棕榈酰转移酶的活性有时可能受到酶附近各种磷脂浓度和组成变化影响的可能性。
