Cis-trans isomerization of the (5-nitro-2-furyl)acrylamide, AF-2, initiated by ascorbate, glutathione, Fe(II) and OH-

The cis-trans isomerization of the (5-nitro-2-furyl)acrylamide, AF-2, has been investigated using some important biological reducing agents to initiate reaction. Physiological concentrations of L-ascorbic acid, glutathione and iron(II) all accomplish isomerization in a catalytic manner over a period of minutes. Base-catalysed isomerization has also been observed. In all cases, the presence of oxygen severely inhibits isomerization. It is proposed that the mechanism involves a free-radical chain process; AF-2 or analogues are thus extremely sensitive probes for the generation of nitro radicals in biochemical reducing systems because of the high efficiency of isomerization.