title: Effect of low-density lipoprotein buoyant density and cholesterol content on the formation of lipoprotein(a) particles.
abstract: Lipoprotein(a) [Lp(a)] is a unique lipoprotein which resembles low-density lipoprotein (LDL) both in lipid composition and the presence of apolipoprotein B-100 (apo B-100). Lp(a) is, however, distinguishable from LDL by the presence of an additional glycoprotein apolipoprotein(a) [apo(a)], which is covalently attached to apo B-100 by a single disulfide bond. It is now generally accepted that Lp(a) assembly is a two-step process in which the initial non-covalent interaction between apo(a) and apo B-100 is mediated by the weak lysine binding sites present in kringle IV types 6, 7 and 8 of apo(a). In the present study, we have investigated the effect of LDL heterogeneity on Lp(a) assembly in a group of 111 individuals. The three parameters of LDL composition assessed in this study were the cholesterol content, the apo B content, and the relative flotation rate (a measure of LDL buoyancy and thus size). We found no correlation between the size of LDL particles and the extent of Lp(a) formation; a weak negative correlation was observed between cholesterol content of LDL and Lp(a) formation (P=0.042). This may suggest a role for free (i.e., surface-associated) cholesterol in the ability of LDL to form Lp(a) particles.
authors.affiliation: Department of Biochemistry, Queen's University, Kingston, ON, Canada.
authors.forename: L
authors.initials: L
authors.lastname: Becker
authors.forename: B R
authors.initials: BR
authors.lastname: Gabel
authors.forename: C A
authors.initials: CA
authors.lastname: Spencer
authors.forename: S M
authors.initials: SM
authors.lastname: Marcovina
authors.forename: M L
authors.initials: ML
authors.lastname: Koschinsky
mesh_terms: D002784:Cholesterol / Q000737:chemistry*; D017270:Lipoprotein(a) / Q000737:chemistry*; D008077:Lipoproteins, LDL / Q000737:chemistry*
chemical_list: D017270:Lipoprotein(a); D008077:Lipoproteins, LDL; D002784:Cholesterol