title: Degradation of human apolipoprotein B-100 by apolipoprotein(a).
abstract: 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.
authors.affiliation: Institute of Biomedical Chemistry, Russian Academy of Medical Sciences, Moscow.
authors.forename: T M
authors.initials: TM
authors.lastname: Chulkova
authors.forename: V V
authors.initials: VV
authors.lastname: Tertov
mesh_terms: D053299:Apolipoprotein B-100; D001053:Apolipoproteins / Q000302:isolation & purification / Q000378:metabolism*; D001055:Apolipoproteins B / Q000378:metabolism*; D053241:Apoprotein(a); D002384:Catalysis; D004591:Electrophoresis, Polyacrylamide Gel; D004789:Enzyme Activation; D006801:Humans; D006868:Hydrolysis; D007610:Kallikreins / Q000378:metabolism; D017270:Lipoprotein(a); D011288:Prekallikrein / Q000378:metabolism; D013379:Substrate Specificity
chemical_list: D053299:Apolipoprotein B-100; D001053:Apolipoproteins; D001055:Apolipoproteins B; D017270:Lipoprotein(a); D011288:Prekallikrein; D053241:Apoprotein(a); D007610:Kallikreins