Olofsson S O, Fager G, Gustafson A
Scand J Clin Lab Invest. 1976 Sep;36(5):481-8. doi: 10.3109/00365517609054467.
High-density lipoproteins (HDL) turn turbid during in vitro incubation, concomitant with the formation of a cholesterol ester-rich lipoprotein, designated HDL-sup. The increase in turbidity (A) formed in relation to incubation time (t) is an asymptotic function: A=Uo(1 - e-k1t), where Uo is the amount of HDL with the property of releasing HDL-sup and k1 the velocity constant of the reaction. The increase in turbidity and formation of HDL-sup was not related to cholesterol ester content of the incubated fraction nor to exogenous factors like bacterial growth. The in vitro incubation was accompanied by a cholesterol esterification with a mean production of 8 nmol cholesterol ester/mg HDL protein, but also by a more pronounced degradation of phosphatidyl choline, 148 nmol/mg HDL protein. These data indicate that the lipid changes are induced by a two-step lecithin:cholesterol acyltransfer (LCAT) reaction. This reaction caused in HDL lipids a consumption of surface material and an increase in 'lipid core', presumably leading to a weakening and disruption of the lipoprotein surface with a recombination of 'lipid core' material in the form of HDL-sup.
高密度脂蛋白（HDL）在体外孵育过程中会变浑浊，同时形成一种富含胆固醇酯的脂蛋白，称为HDL-sup。与孵育时间（t）相关的浊度增加（A）是一个渐近函数：A = Uo(1 - e-k1t)，其中Uo是具有释放HDL-sup特性的HDL量，k1是反应的速度常数。浊度的增加和HDL-sup的形成与孵育组分的胆固醇酯含量无关，也与细菌生长等外源性因素无关。体外孵育伴随着胆固醇酯化，平均产生8 nmol胆固醇酯/mg HDL蛋白，但也伴随着更明显的磷脂酰胆碱降解，为148 nmol/mg HDL蛋白。这些数据表明，脂质变化是由两步卵磷脂：胆固醇酰基转移酶（LCAT）反应诱导的。该反应导致HDL脂质表面物质消耗和“脂质核心”增加，可能导致脂蛋白表面减弱和破坏，“脂质核心”物质以HDL-sup的形式重新组合。
