Oat leaf phosphoglucose isomerase: competitive inhibition by erythrose-4-phosphate.

Phosphoglucose isomerase was partially purified from oat leaves and shown to be strongly inhibited by erythrose-4-P. Estimated Ki values were between 0.4 and 4.0 μM. The inhibition was of the competitive type with respect to either of the substrates glucose-6-P and fructose-6-P. Several other plant phosphoglucose isomerases were found to be similarly sensitive to erythrose-4-P.