Fructosamine-3-kinase involved in protein deglycation by mediating phosphorylation of fructoselysine residues on glycated proteins, to generate fructoselysine-3 phosphate (PubMed:11016445, PubMed:11522682, PubMed:11975663). Fructoselysine-3 phosphate adducts are unstable and decompose under physiological conditions (PubMed:11522682, PubMed:11975663). Involved in intracellular deglycation in erythrocytes (PubMed:11975663). Involved in the response to oxidative stress by mediating deglycation of NFE2L2/NRF2, glycation impairing NFE2L2/NRF2 function (By similarity). Also able to phosphorylate psicosamines and ribulosamines (PubMed:14633848). ATP + N(6)-(D-fructosyl)-L-lysyl-[protein] = ADP + H(+) + N(6)-(3-O-phospho-D-fructosyl)-L-lysyl-[protein] ATP + N(6)-D-ribulosyl-L-lysyl-[protein] = ADP + H(+) + N(6)-(3-O-phospho-D-ribulosyl)-L-lysyl-[protein] ATP + N(6)-(D-psicosyl)-L-lysyl-[protein] = ADP + H(+) + N(6)-(3-O-phospho-D-psicosyl)-L-lysyl-[protein] Monomer. Widely expressed (PubMed:11522682). Expressed in erythrocytes (PubMed:11016445). Belongs to the fructosamine kinase family.