Direct evidence of the Entner-Doudoroff pathway operating in the metabolism of D-glucosamine in bacteria.
Pseudomonas fluorescens (Migula) (IFO 14808) has both a membrane-bound PQQ-dependent D-glucose (D-Glc) dehydrogenase [EC 1.1.99.17] [which also acts on D-glucosamine (D-GlcN)] and a PLP-dependent D-glucosaminate (D-GlcNA) dehydratase [EC 4.2.1.26]. Further, these two enzymes were induced when D-GlcN was added to the culture medium. However, D-glucosamine-6-phosphate (D-GlcN-6-P) isomerase [EC 5.3.1.10], another enzyme involved in the metabolism of D-GlcN, was only present at a low level in this bacterium. The bacterium was able to grow in a minimal medium containing D-GlcN or D-GlcNA as the sole source of carbon and nitrogen. Intact cells of P. fluorescens (Migula) converted D-GlcN to D-GlcNA and then to 2-keto-3-deoxy-D-gluconate (KDGA). These results demonstrate that D-GlcN is metabolized via D-GlcNA to KDGA in P. fluorescens (Migula) (Entner-Doudoroff pathway). In contrast, Enterobacter cloacae(IFO 13535) and Agrobacterium radiobacter (IAM 1526) have significant amounts of D-GlcN-6-P isomerase with low levels of the D-Glc dehydrogenase and D-GlcNA dehydratase. Further, only the isomerase activity was induced on the addition of D-GlcN to the culture medium. These results demonstrate that there is a new route (Entner-Doudoroff pathway), i.e., in addition to the known one (Embden-Meyerhof pathway), for the metabolism of D-GlcN in bacteria and one of the two routes is predominant in the each of bacteria examined.
Iwamoto
R
R
Department of Chemistry, Faculty of Science, Nara Women's University.
Imanaga
Y
Y
D019747:Aldose-Ketose Isomerases; D001419:Bacteria / Q000378:metabolism*; D002118:Calcium / Q000494:pharmacology; D002238:Carbohydrate Epimerases / Q000378:metabolism; D004754:Enterobacter / Q000378:metabolism; D005944:Glucosamine / Q000378:metabolism*; D042843:Glucose 1-Dehydrogenase; D005948:Glucose Dehydrogenases / Q000378:metabolism; D006836:Hydro-Lyases / Q000378:metabolism; D045542:PQQ Cofactor; D011551:Pseudomonas fluorescens / Q000378:metabolism; D015363:Quinolones / Q000494:pharmacology; D012231:Rhizobium / Q000378:metabolism
D015363:Quinolones; D045542:PQQ Cofactor; D005948:Glucose Dehydrogenases; D042843:Glucose 1-Dehydrogenase; C020582:glucosamine-6-phosphate isomerase; D006836:Hydro-Lyases; C018870:aminodeoxygluconate dehydratase; D002238:Carbohydrate Epimerases; D019747:Aldose-Ketose Isomerases; D005944:Glucosamine; D002118:Calcium