SYNTHESIS AND BIOLOGICAL PROPERTIES OF 2-SUBSTITUTED MYOINOSITOL 1,4,5-TRISPHOSPHATE ANALOGS DIRECTED TOWARD AFFINITY-CHROMATOGRAPHY AND PHOTOAFFINITY-LABELING

A series of myo-inositol 1,4,5-trisphosphate analogues with the 2-acyl substituents p-aminobenzoyl (7), p-azidobenzoyl (8), 4-(5-[2-(benzamido)ethyl]-2-hydroxyphenylazo}benzoyl (9), and cis,trans-4-aminocyclobexylcarbonyl (10) were synthesised and examined for their effects on the 5-phosphatase, the 3-kinase, the tritiated trisphosphate-binding activity, and the Ca2+-releasing activity. Each analogue inhibited the hydrolysis of D-[5-P-32]Ins(1,4,5)P, and the phosphorylation of D-[H-3]Ins(1,4,5)P3, catalysed by erythrocyte ghosts and brain cytosol, respectively. The analogues acted as full agonists in releasing Ca2+ from permeabilised cells and also inhibited the binding of D-[H-3]Ins(1,4,5)P3 to cerebellum microsomes. The analogues 7 and 10 were utilised for immobilisation of the trisphosphate on Sepharose(TM) and the subsequent affinity chromatography effected purification of the above proteins. A photoaffinity probe, the appendage of which acted as the photoaffinity probe as well as a non-radioactive molecular marker, was also derived from the analogue 7.