Non-enzymatic incorporation of phosphate into soya bean proteins

Soya bean reserve proteins were phosphorylated with ironIII and ATP or PP. In the case of ATP, a transfer of the triphosphate moiety to the protein was observed. This phosphorylation was very sensitive to the oxidation state and polynucleation of iron, no incorporation being observed with ironII. Up to 0 . 2 mol . PP and 1 . 15 mol of iron per mole of beta-conglycinin, and 0 . 25 mol PP and 1 . 06 mol of iron per mole glycinin were incorporated. The phosphorylated proteins were stable under the conditions of TCA precipitation and high ionic strength. The chemical link was not likely to be a phosphoester as deduced from the acidic stability study. Phosphate was certainly incorporated as a complex with iron into the proteins.