The identification and partial characterization of acetaldehyde adducts of hemoglobin occurring in vivo: a possible marker of alcohol consumption.

Chromatographic, peptide mapping and mass spectrometric analysis were used to examine hemoglobin (Hb) from heavy drinkers and abstainers for alcohol consumption-related modifications. Heavy drinker and abstainer hemoglobin samples contained similar amounts of glycosylated Hb and significantly different (p < 0.05) amounts of "fast" hemoglobin. The presence of higher amounts of "fast" Hb in heavy drinker relative to abstainer samples suggested the presence of alcohol-consumption related modifications. To further examine Hb for modifications, tryptic peptides of the "fast" hemoglobin HbA1c were isolated and analyzed by plasma desorption mass spectrometry (PDMS). [14C]acetaldehyde (AcH)-Hb was synthesized in vivo for use as a standard. Specific peptides were chosen based on co-migration with radiolabeled peptides from a tryptic digest of the [14C]acetaldehyde-Hb. The masses obtained by PDMS for two heavy drinker peptides were identical to two radiolabeled peptides; the two pairs of peptides co-migrated on HPLC. A comparison of the observed mass for the peptides with the theoretical masses for acetaldehyde-modified Hb peptides suggested that the peptides were AcH-modified alpha and beta chain N-termini of Hb. The modified peptides were found in five of six heavy drinker samples. This is the first description of site-specific AcH-Hb adducts occurring in vivo. The routine detection of such adducts has potential for characterizing usual alcohol intake.