title: The susceptibility of lipoprotein(a) to copper oxidation is correlated with the susceptibility of autologous low density lipoprotein to oxidation.
abstract: OBJECTIVE
  Lipoprotein(a) [Lp(a)] can be oxidized by copper in vitro in a way comparable to low-density lipoprotein (LDL). We sought to determine whether the susceptibility of Lp(a) to oxidation is correlated with the susceptibility of autologous heterogeneous LDL, with apolipoprotein(a) [apo(a)] molecular size, or with both factors.
  
  
  METHODS
  We examined shifts in electrophoretic mobility of Lp(a) and LDL caused by copper oxidation in plasma samples from 81 healthy men. The effect of copper oxidation on different-sized apo(a) was also evaluated.
  
  
  RESULTS
  There was a close correlation between the relative electrophoretic mobilities of oxidized Lp(a) and oxidized LDL in subjects, especially with small-sized apo(a) (n = 25, r = 0.72, p < 0.0001). Oxidative processes in Lp(a) resulted in the degradation of large-, but not small-sized apo(a).
  
  
  CONCLUSIONS
  The susceptibility of Lp(a) to oxidation is correlated with that of autologous LDL. Large-sized apo(a) may be involved in the Lp(a) oxidation.
authors.affiliation: First Department of Internal Medicine, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-0042, Japan. nakake20@aol.com
authors.forename: Kei
authors.initials: K
authors.lastname: Nakajima
authors.forename: Takeshi
authors.initials: T
authors.lastname: Yamashita
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Kusuhara
authors.forename: Atsushi
authors.initials: A
authors.lastname: Yonemura
authors.forename: Toshimitsu
authors.initials: T
authors.lastname: Ito
authors.forename: Kenji
authors.initials: K
authors.lastname: Higashi
authors.forename: Makoto
authors.initials: M
authors.lastname: Ayaori
authors.forename: Reiko
authors.initials: R
authors.lastname: Ohmori
authors.forename: Haruo
authors.initials: H
authors.lastname: Nakamura
authors.forename: Fumio
authors.initials: F
authors.lastname: Ohsuzu
mesh_terms: D000328:Adult; D000368:Aged; D003300:Copper / Q000737:chemistry*; D004586:Electrophoresis / Q000379:methods; D006801:Humans; D015227:Lipid Peroxidation; D017270:Lipoprotein(a) / Q000097:blood / Q000737:chemistry*; D008077:Lipoproteins, LDL / Q000097:blood / Q000737:chemistry*; D008297:Male; D008875:Middle Aged; D010084:Oxidation-Reduction
chemical_list: D017270:Lipoprotein(a); D008077:Lipoproteins, LDL; D003300:Copper