Ramos, Luiz D.
Mantovani, Mariana C.
[3, 4, 1]
Stevani, Cassius V.
Bechara, Etelvino J. H.
Total Authors: 6
 Univ Sao Paulo, Dept Quim Fundamental, Sao Paulo, SP - Brazil
 UniA, Ctr Univ Anhanguera, Santo Andre, SP - Brazil
 Univ Fed Sao Paulo, Inst Ciencias Ambientais Quim & Farmaceut, Diadema, SP - Brazil
 Univ Sao Paulo, Inst Pesquisas Energet & Nucl, Sao Paulo, SP - Brazil
 Univ Cruzeiro Sul, Ctr Ciencias Exatas & Tecnol, Sao Paulo, SP - Brazil
Total Affiliations: 5
Free Radical Biology and Medicine;
Web of Science Citations:
Aminoacetone (1-aminopropan-2-one), a putative minor biological source of methylglyoxal, reacts like other ?-aminoketones such as 6-aminolevulinic acid (first heme precursor) and 1,4-diaminobutanone (a microbicide) yielding electrophilic ?-oxoaldehydes, ammonium ion and reactive oxygen species by metal- and hemeproteincatalyzed aerobic oxidation. A plethora of recent reports implicates triose phosphate-generated methylglyoxal in protein crosslinking and DNA addition, leading to age-related disorders, including diabetes. Importantly, methylglyoxal-treated hemoglobin adds four water-exposed arginine residues, which may compromise its physiological role and potentially serve as biomarkers for diabetes. This paper reports on the co-oxidation of aminoacetone and oxyhemoglobin in normally aerated phosphate buffer, leading to structural changes in hemoglobin, which can be attributed to the addition of aminoacetone-produced methylglyoxal to the protein. Hydroxyl radical-promoted chemical damage to hemoglobin may also occur in parallel, which is suggested by EPR-spin trapping studies with 5,5-dimethyl-1-pyrroline-N-oxide and ethanol. Concomitantly, oxyhemoglobin is oxidized to methemoglobin, as indicated by characteristic CD spectral changes in the Soret and visible regions. Overall, these findings may contribute to elucidate the molecular mechanisms underlying human diseases associated with hemoglobin dysfunctions and with aminoacetone in metabolic alterations related to excess glycine and threonine. (AU)