Two isoforms of Rubisco activase in cotton, the products of separate genes not alternative splicing.

In several plant species, ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) activase consists of two isoforms that are produced by alternative splicing of a pre-mRNA. Two forms of activase corresponding to the longer, redox-regulated alpha and the shorter, beta forms were detected immunologically in cotton (Gossypium hirsutum L.) leaves, but their N-termini differed in 4 of 14 residues.