Identification of Plasma Protein Markers of Oxidation in Obese Men

Aim: Pyrrole modifications to proteins are a sign of oxidative damage, they are not present in newly-formed proteins but occur when lipid oxidation products or sugars react non-enzymicly with free amino groups. Studying such modifications will enable the development of novel biomarkers of oxidative stress. We recently published methodology to detect and identify pyrrole-containing proteins by combining biotin-labelled Ehrlich’s reagent (ER-B) to specifically target protein bound pyrroles, 2D electrophoresis and LC/MS/MS. We hypothesize that plasma from obese subjects should contain pyrrolised proteins as the obese have increased oxidative stress.
Method: Our objective in this study was to use the technique described above to investigate the profile of these modified proteins in plasma samples from two groups of male age-matched volunteers, obese (BMI > 30) matched for adiposity (waist circumference) and lean (BMI 22-25) (n=4 per group).
Results: There was a discernable difference in the pattern of pyrrole-containing proteins between the two groups. All lean-plasma samples contained a small number of pyrrolised-proteins (up to a maximum of 4 proteins); while all obese-plasma samples had approximately four times as many different pyrrole-containing proteins. This demonstrates that this methodology has the sensitivity and specificity required to detect and identify proteins modified by oxidation in blood plasma from human subjects.