TABLE 1

Protein and lipid oxidation products in LDL incubated with glucose

o-Tyrosine (mmol/mol)m-Tyrosine (mmol/mol)HODE (nmol/mg)
LDL0.15 ± 0.010.11 ± 0.010.94 ± 0.02
LDL + glucose0.25 ± 0.01*0.18 ± 0.011.42 ± 0.09*
LDL + BHT0.15 ± 0.010.11 ± 0.010.97 ± 0.06
LDL + glucose + BHT0.15 ± 0.010.12 ± 0.010.94 ± 0.03
LDL + copper0.42 ± 0.05*0.28 ± 0.06*1.85 ± 0.22*
  • Data are means ± SE of 12 independent determinations. LDL (1 mg/ml) in PBS (pH 7.4) supplemented with 0.1 mmol/l EDTA was incubated for 10 days at 37°C. Where indicated, the reaction mixture was supplemented with 25 mmol/l glucose and/or 25 μmol/l BHT. For copper oxidation, LDL was incubated for 24 h in the presence of 20 μmol/l copper sulfate without EDTA. Reactions were terminated by adding 0.2 mmol/l DTPA, 300 nmol/l catalase, and 0.1 mmol/l BHT. Amino acids composition and HODE content of LDL were determined as described in research design and methods. LDL + copper was used as a positive control, and this value is based on six independent determinations. Levels of oxidized amino acids are normalized to levels of precursor amino acid (mmol/mol phenylalanine). Levels of HODE are normalized to LDL protein (nmol/mg).

  • *

    * P < 0.001 and

  • P < 0.01, by one-way ANOVA when compared with LDL alone.