ATP Specifically Bound as a Hapten to a Monoclonal Anti-Phospholipid Antibody Retains Phosphate Donor Activity

Abstract We have previously reported that each of four monoclonal antibodies to a phospholipid, phosphatidylinositol phosphate (PIP), has a phosphate binding subsite in the antigen binding site that can bind ATP (Molec. Immunol. 21 , 863-868, 1984). We have now observed that antibody-bound ATP has the ability to donate a phosphate group in the phosphorylation reaction of glucose to glucose-6-phosphate catalyzed by hexokinase. The phosphorylation reaction proceeds equally efficiently when ATP is provided as free (nonbound) ATP or as antibody-bound ATP. We conclude that an anti-phospholipid antibody can serve as a carrier of a functionally active nucleotide.