UV-INDUCED CROSS-LINKING OF ABSCISIC ACID TO BINDING PROTEINS

Article abstract of DOI:10.1016/0031-9422(95)00170-C

Conditions for UV-induced cross-linking of abscisic acid (ABA) through its enone chromophore to binding proteins are evaluated.The effects of a UV-light band between 260 and 530 nm of both unconjugated and protein-conjugated ABA, as well as on anti-ABA antibodies as models of ABA-binding proteins were determined.UV irradiation caused both isomerization and photolysis of ABA, but increasing the lower irradiation boundary to 345 nm strongly reduced photolysis and largely prevented isomerization.When conjugated to alkaline phosphatase (AP), ABA remained stable when using either a 320 or a 345 mn filter.At these wavelenghts both bonding of ABA to antibodies as well as AP enzymatic activity were maintained.UV-induced cross-linking of monoclonal anti-ABA antibodies to immobilized ABA was analysed by immunoassays.Optimal cross-linking was achieved after a 5 min irradiation period at 0 deg C, using a long pass, cut-on filter to quench wavelengths below 290 nm.This cross-linking faithfully reflected cognate binding activity.