Studies on reaction of formaldehyde with naturally occurring thiol compounds and ascorbic acid

Abstract

To gain insight into possible cellular protective mechanisms against the insult of formaldehyde, we have investigated this molecule's reactivity with both naturally occurring thiol compounds including glutathione and L-ascorbic acid. By UV measurements, formaldehyde was found to rapidly react with glutathione forming an S-hydroxymethyl covalent adduct. The adduct which was confirmed by NMR is transiently stable. Formaldehyde is also significantly reactive with L-ascorbic acid in a reaction which was observed to be dissimilar to its reaction with dimedone. The reaction of formaldehyde with glutathione was reduced by 40% in the presence of an excess amount of L-ascorbic acid, due to the trapping of formaldehyde by L-ascorbic acid. The data suggest that L-ascorbic acid may have a possiblein vivo role in the metabolism of formaldehyde, thereby protecting cellular glutathione from possible depletion.