Glucose Uptake and Phosphorylation in Pseudomonas fluorescens

Abstract

Pseudomonas 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 [ 14 C]glucose-uptake rates in parent and gox-7 cells were qualitatively similar. Initial [ 14 C]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.