Fe(III)-[N-(C-5-[deoxy-beta-D-glucosyl]-2,3-dihydroxybenzoyl)-L-serine]2 + H2O + H(+) = Fe(III)-[N-(C-5-[deoxy-beta-D-glucosyl]-2,3-dihydroxybenzoyl)-L-serine] + N-(C-5-[deoxy-beta-D-glucosyl]-2,3-dihydroxybenzoyl)-L-serine — reaction