Synthesis and biological properties of 2-substituted myo-inositol 1,4,5-trisphosphate analogues 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-aminocyclohexylcarbonyl (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-[5-³²P]Ins(1,4,5)P₃ and the phosphorylation of d-[³H]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-[³H]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.