Severson D L, Fletcher T
Can J Physiol Pharmacol. 1985 Aug;63(8):944-51. doi: 10.1139/y85-156.
Enzymatic pathways involved in the metabolism of lysophosphatidylcholine were investigated in rat heart myocardial cells. Acyl CoA-dependent acyltransferase activity was localized in microsomes, and was much greater than lysophospholipase activity in either cytosolic or microsomal fractions. The cytosolic lysophospholipase was more sensitive to inhibition by palmitylcarnitine in comparison to free fatty acids. In contrast, free fatty acids (oleate and palmitate) produced a greater inhibition of the microsomal acyltransferase and lysophospholipase than did palmitylcarnitine. A reduction in the assay pH to 6.5 resulted in an increase in microsomal acyltransferase and cytosolic lysophospholipase activities, but brought about a marked reduction in the microsomal lysophospholipase activity. At pH 6.5, the percentage inhibition of the microsomal acyltransferase by palmitylcarnitine was reduced, whereas the inhibition by palmitic acid was enhanced. The inhibition of the microsomal lysophospholipase by both palmitylcarnitine and palmitic acid was reduced at pH 6.5. With respect to myocardial ischemia, the inhibition of microsomal acyltransferase by free fatty acids and the reduction in microsomal lysophospholipase activity due to acidosis may contribute to the elevation of cellular lysophosphoglycerides which are arrhythmogenic.
在大鼠心脏心肌细胞中研究了参与溶血磷脂酰胆碱代谢的酶促途径。酰基辅酶A依赖性酰基转移酶活性定位于微粒体中，并且在胞质或微粒体组分中均远大于溶血磷脂酶活性。与游离脂肪酸相比，胞质溶血磷脂酶对棕榈酰肉碱的抑制更敏感。相反，游离脂肪酸（油酸和棕榈酸）对微粒体酰基转移酶和溶血磷脂酶的抑制作用比棕榈酰肉碱更强。将测定pH降至6.5会导致微粒体酰基转移酶和胞质溶血磷脂酶活性增加，但会使微粒体溶血磷脂酶活性显著降低。在pH 6.5时，棕榈酰肉碱对微粒体酰基转移酶的抑制百分比降低，而棕榈酸的抑制作用增强。在pH 6.5时，棕榈酰肉碱和棕榈酸对微粒体溶血磷脂酶的抑制作用均降低。关于心肌缺血，游离脂肪酸对微粒体酰基转移酶的抑制以及酸中毒导致的微粒体溶血磷脂酶活性降低可能导致具有致心律失常作用的细胞溶血甘油磷脂升高。
