Fructosamine-3-kinase involved in protein deglycation by mediating phosphorylation of fructoselysine residues on glycated proteins, to generate fructoselysine-3 phosphate . Fructoselysine-3 phosphate adducts are unstable and decompose under physiological conditions (By similarity). Involved in intracellular deglycation in erythrocytes and pancreatic islets.