Holian O, Nelson R
Department of Surgery University of Illinois College of Medicine, Chicago 60680.
Anticancer Res. 1992 May-Jun;12(3):975-80.
The results presented in this paper indicate that long chain free fatty acids have a dual modulatory effect on Protein Kinase C (PKC) activity purified from rat colon. Saturated (stearic) and monounsaturated (oleic) fatty acids are weak activators of PKC in the absence of phosphatidyl serine (PS) and diolein (DO), but have no significant effect on the PS/DO stimulated activity. Increasing the degree of unsaturation of the fatty acid, such as linolenic, arachidonic and eicosapentaenoic acids, also increases their stimulatory action toward unstimulated PKC, as well as their inhibition of PS/DO stimulated enzyme activity. Within this group of fatty acids there is no significant difference in the response of PKC toward omega-6 versus omega-3 type fatty acids. However, docosahexaenoic acid, a 22 carbon omega-3 polyunsaturated fatty acid found primarily in fish oil affected PKC differently from all other fatty acids studied. This compound was unable to stimulate dormant PKC activity, but was a highly potent inhibitor of PS/DO stimulated PKC. It is hypothesized that the inhibitory action of this omega-3 fatty acid may contribute to the protective role of fish oil consumption on colon tumorigenesis.
本文呈现的结果表明，长链游离脂肪酸对从大鼠结肠中纯化的蛋白激酶C（PKC）活性具有双重调节作用。在不存在磷脂酰丝氨酸（PS）和二油精（DO）的情况下，饱和（硬脂酸）和单不饱和（油酸）脂肪酸是PKC的弱激活剂，但对PS/DO刺激的活性没有显著影响。增加脂肪酸的不饱和度，如亚麻酸、花生四烯酸和二十碳五烯酸，也会增强它们对未刺激的PKC的刺激作用，以及对PS/DO刺激的酶活性的抑制作用。在这组脂肪酸中，PKC对ω-6型和ω-3型脂肪酸的反应没有显著差异。然而，二十二碳六烯酸，一种主要存在于鱼油中的22碳ω-3多不饱和脂肪酸，对PKC的影响与所研究的所有其他脂肪酸不同。这种化合物无法刺激静止的PKC活性，但却是PS/DO刺激的PKC的高效抑制剂。据推测，这种ω-3脂肪酸的抑制作用可能有助于解释食用鱼油对结肠肿瘤发生的保护作用。
