Oxymethurea

Oxymethurea (Dimethylolurea) is a formaldehyde-releasing protein modification reagent. Under acidic conditions, Oxymethurea promotes nucleophilic substitution of tyrosine via protonation of its hydroxymethyl group, while under alkaline conditions, it promotes protein crosslinking by converting the phenolic hydroxyl group of tyrosine into a more nucleophilic phenoxide ion. Oxymethurea can be used in studies related to protein chemical modification, protein crosslinking, protein protection and genotoxicity^[1][2][3]. In Vitro:Oxymethurea (Dimethylolurea) is a positive mutagen in the in vitro Ames test, which correctly predicts its mutagenicity, whereas TOPKAT and CASETOX incorrectly predict it as a non-mutagen^[1].
Oxymethurea (DMU; DMU/BSA mass ratio of 2:5; pH 9.0; room temperature) modifies tyrosine residues in BSA in a time-dependent manner, with modification rates of approximately 14%, 31% and 70% at 4, 8 and 24 h, respectively^[2].
Oxymethurea (0.21-8.33 μmol per plate; 30 min pre-incubation, 48 h or 72 h incubation) induces concentration-dependent mutagenicity in Salmonella typhimurium strains TA98, TA100 and TA102 with or without metabolic activation; at concentrations of 2.08 to 8.33 μmol per plate, the number of revertant colonies doubles^[3].
Oxymethurea (3.3-333 μmol/l; 48 h without S9, 3 h with S9 plus 45 h additional culture) induces a weak concentration-dependent increase in micronuclei in V79 Chinese hamster cells only under non-metabolically activated conditions, with the micronucleus rate reaching 3.0% at the concentration of 333 μmol/l, but shows no effect in the presence of metabolic activation^[3].
Oxymethurea (up to 10 mmol/l; 15 min) does not affect the assembly of tubulin isolated from porcine brain into microtubules^[3]. In Vivo:Dimethylolurea (30 g per 300 g of casein; oral feeding; 24 days)-treated casein maintains nearly equivalent protein efficiency ratio (2.77) to untreated casein (2.83) in healthy Rattus norvegicus^[2].