Pawelczyk T, Lowenstein J M
Department of Clinical Biochemistry, Medical University of Gdansk, Poland.
Biochimie. 1997 Dec;79(12):741-8. doi: 10.1016/s0300-9084(97)86932-5.
Bovine brain sphingomyelin was separated into different molecular species using a reverse phase column. PLC delta 1 was inhibited by all molecular species of sphingomyelin. The extent of this inhibition was dependent on the hydrophobicity. Based on fatty acid analysis, we conclude that the inhibition of PLC delta 1 depends on the chain length and degree of unsaturation of the fatty acid moiety of SM. N-palmitoyl-D-sphingomyelin and N-stearoyl-D-sphingomyelin inhibited PLC delta 1 less then N-oleoyl-D-sphingomyelin. In the absence of Ca2+ (1 mM EGTA) all tested molecular species of SM inhibited weakly the enzyme. The sensitivity of PLC delta 1 to inhibition by SM increased with increasing Ca2+ concentration. The shape of calcium curve differed for molecular species with saturated and unsaturated fatty acids. Inhibition of PLC delta 1 by N-palmitoyl-D-sphingomyelin and N-stearoyl-D-sphingomyelin reached a maximum at 0.2 microM Ca2+, while inhibition by N-oleoyl-D-sphingomyelin reached maximum at 2 microM Ca2+. PLC delta 1 is more sensitive to inhibition by SM when it is maximally activated by spermine and calcium and the extent of this inhibition depends on the length and degree of fatty acid unsaturation of the molecular species.
使用反相柱将牛脑鞘磷脂分离成不同的分子种类。鞘磷脂的所有分子种类均能抑制磷脂酶Cδ1（PLCδ1）。这种抑制程度取决于疏水性。基于脂肪酸分析，我们得出结论，PLCδ1的抑制作用取决于鞘磷脂（SM）脂肪酸部分的链长和不饱和度。N-棕榈酰-D-鞘磷脂和N-硬脂酰-D-鞘磷脂对PLCδ1的抑制作用小于N-油酰-D-鞘磷脂。在不存在Ca2+（1 mM乙二醇双（2-氨基乙基醚）四乙酸）的情况下，所有测试的SM分子种类对该酶的抑制作用较弱。PLCδ1对SM抑制作用的敏感性随Ca2+浓度的增加而增加。饱和脂肪酸和不饱和脂肪酸的分子种类的钙曲线形状不同。N-棕榈酰-D-鞘磷脂和N-硬脂酰-D-鞘磷脂对PLCδ1的抑制作用在0.2 microM Ca2+时达到最大值，而N-油酰-D-鞘磷脂的抑制作用在2 microM Ca2+时达到最大值。当PLCδ1被精胺和钙最大程度激活时，它对SM抑制作用更敏感，且这种抑制程度取决于分子种类的脂肪酸长度和不饱和度。
