Glucose uptake and phosphorylation in Pseudomonas fluorescens

Abstract

P. fluorescens ATCC 13525 and a particulate glucose oxidase (D glucose : oxygen oxidoreductase, EC 1.1.3.4) mutant of this organism, gox 7, were examined to determine if glucose oxidation via particulate glucose oxidase is a required first step for glucose uptake. Initial [14C] glucose uptake rates in parent and gox 7 cells were qualitatively similar. Initial [14C] glucose uptake product analysis revealed that glucose was accumulated via active transport and was rapidly metabolized to glucose 6 phosphate and gluconate 6 phosphate in both parent and gox 7 cells. Cell extracts contained soluble adenosine 5' triphosphate specific kinase activity for phosphorylation of glucose. Glucose uptake was induced by glucose and not gluconate, thus, establishing independent regulation of glucose transport and glucose catabolism in P. fluorescens. The results prove that glucose oxidase was not an obligatory reaction for glucose carbon permeation in P. fluorescens. A general unifying scheme for glucose utilization in the aerobic fluorescent pseudomonads is suggested for the purpose of clarifying glucose uptake in these bacteria.