Chulkova T M, Tertov V V
Institute of Biomedical Chemistry, Russian Academy of Medical Sciences, Moscow.
FEBS Lett. 1993 Dec 27;336(2):327-9. doi: 10.1016/0014-5793(93)80830-n.
Human plasma low density lipoproteins (LDL) contain a very high molecular weight protein termed apoB-100 (M(r) = 550,000). In many samples of LDL, minor components designated as apoB-74 (M(r) = 407,000) and apoB-26 (M(r) = 145,000) are present. It has been shown that they can arise as a result of proteolytic degradation of apoB-100. Our earlier studies demonstrated that the active forms of lipoprotein(a) (LP(a)) and apolipoprotein(a) (apo(a)) possess proteolytic activity. In the present study we investigated the possibility of apoB-100 degradation in the presence of activated apo(a). LDL were incubated with the purified apo(a) and analyzed by SDS-polyacrylamide gel electrophoresis. It was found that apoB is cleaved by apo(a) with formation of proteolytic fragments including B-74 and B-26. The physiological significance of apoB degradation under the action of apo(a) is considered.
人血浆低密度脂蛋白（LDL）含有一种分子量非常高的蛋白质，称为载脂蛋白B-100（M(r)=550,000）。在许多LDL样本中，存在被指定为载脂蛋白B-74（M(r)=407,000）和载脂蛋白B-26（M(r)=145,000）的次要成分。已表明它们可能是载脂蛋白B-100蛋白水解降解的结果。我们早期的研究表明，脂蛋白(a)（LP(a)）和载脂蛋白(a)（apo(a)）的活性形式具有蛋白水解活性。在本研究中，我们研究了在活化的apo(a)存在下载脂蛋白B-100降解的可能性。将LDL与纯化的apo(a)一起孵育，并通过SDS-聚丙烯酰胺凝胶电泳进行分析。发现apo(a)可切割apoB，形成包括B-74和B-26在内的蛋白水解片段。还考虑了在apo(a)作用下apoB降解的生理意义。
