AFB1lysine

AFB1-lysine (AFB1-lys) is an albumin adduct formed when aflatoxin B1, a mycotoxin produced by certain Aspergillus species, reacts with the lysine residues of serum albumin. The reactive metabolite aflatoxin B1-8,9-epoxide, produced in mammals from AFB1, forms a covalent bond with the ε-amino group of lysine residues, yielding the AFB1-lysine adduct. This adduct is one of the most commonly measured biomarkers of aflatoxin exposure in humans because albumin is abundant in blood and has a relatively long circulating half-life.

Detecting AFB1-lysine in serum or plasma provides an integrated estimate of exposure over the preceding weeks to months, depending on albumin turnover. Levels are typically reported as the amount of AFB1-lysine per unit of albumin, commonly as picograms of AFB1-lysine per milligram of albumin (pg/mg). Analytical methods include liquid chromatography–tandem mass spectrometry (LC-MS/MS), high-performance liquid chromatography with fluorescence detection, and immunoassays, often after enzymatic or chemical release of the adduct from albumin.

AFB1-lysine measurement is widely used in epidemiological and clinical studies to assess exposure to aflatoxins, particularly in regions with high dietary contamination from foods such as maize, peanuts, and other stored staples. Higher levels of the adduct have been associated with increased risk of hepatocellular carcinoma, especially in individuals with hepatitis B virus infection, though AFB1-lysine provides a surrogate marker rather than a direct measure of DNA damage.