Immunological Characterization of the Pyrophosphate Dependent Fructose-6-Phosphate Phosphotransferase

The pyrophosphate dependent phosphofructokinase (PFP, EC 2.7.1.90[EC])was purified from potato tubers, bean seeds and cucumber seeds.The PFP of all three species appears to contain two subunitswith a molecular weight of approximately 60,000 and 66,000 dalton.The purified proteins were used as the antigens to produce polyclonalantibodies in rabbits. Two of the obtained sera (anti-potatoPFP and anti-cucumber PFP) proved to be monospecific for thePFP polypeptides on protein blots. The antipotato serum crossreacts with the PFP from all the tested higher plant specieson protein blots, but no cross reaction with the PFP of Propionibacteriumsharmanii was found. This shows that the PFP subunits from thehigher plant species have similar antigenic determinants inthe primary structure but differes largely from that of thePropionibacterium. The differences observed in the efficiencyof the sera to inactivate the PFP from the different species,however, indicate that the surface antigenic determinants onthe native PFP enzymes differ between the higher plant speciesand even within the Cucurbitaceae. (Received June 15, 1987; Accepted November 20, 1987)