THE IDENTIFICATION AND PARTIAL CHARACTERIZATION OF ACETALDEHYDE ADDUCTS OF HEMOGLOBIN OCCURRING INVIVO - 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). [C-14]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 [C-14]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.