Response to “Malondialdehyde-Induced Post-Translational Modification of Human Hemoglobin”

Although malondialdehyde and methylglyoxal have the same molecular formula, they have different chemistry in forming protein adducts. The major lysine adduct of malondialdehyde in hemoglobin is the N-propenal type, while that of methylglyoxal is N 6-(1-carboxyethyl)­lysine. This Letter provides evidence that the “methylglyoxal-like” hemoglobin adducts are not derived from malondialdehyde. This Letter also discusses the quantification of malondialdehyde-induced post-translational modifications in human hemoglobin by different mass spectrometry-based methods.