Cytokinin oxidase — purification by affinity chromatography and activation by caffeic acid

Abstract

Two cytokinin analogues, 6-di-(isopent-2-enyl)aminopurine and 6-( N-isopent-2-enyl- N-methylamino)purine were found to be effective inhibitors of cytokinin oxidase prepared from tobacco tissue cultures expressing the cytokinin biosynthesis gene ipt. The latter analogue was conjugated at the N-9 position to Sepharose through a 12-atom spacer moiety. This yielded a matrix for preparation of an affinity column for further purification of cytokinin oxidase that had been partially purified by other methods. The activity of cytokinin oxidase was enhanced by caffeic acid and to a lesser extent by other phenolic compounds tested.