Two types of structural analogues of D-myo-inositol 1,4,5-trisphosphate [Ins(1,4,5)P.sub.4 ] are prepared by a chemo-enzymatic route. These 6-O-substituted analogues retain the biological activity of Ins(1,4,5)P.sub.3 and are able to elicit Ca.sup.2+ release from porcine brain microsomes. Moreover, these analogues allow the preparation of Ins(1,4,5)P.sub.3 -based immunogens and affinity matrix which are successfully applied to the preparation and purification of antibodies against Ins(1,4,5)P.sub.3. These antibodies display discriminative affinity toward Ins(1,4,5)P.sub.3, and provide a useful tool to study intracellular Ca.sup.2+ mobilization.