title: Metabolism of D-arabinose by Aerobacter aerogenes: purification of the isomerase.
abstract: In Aerobacter aerogenes, the mutational event permitting the utilization of d-arabinose as a source of carbon and energy is a regulatory mutation resulting in the constitutive synthesis of certain enzymes of the l-fucose catabolic pathway. l-Fucose isomerase catalyzes the isomerization of d-arabinose to d-ribulose. This enzyme was purified to homogeneity as indicated by a single band in disc-gel electrophoretic columns and single peaks with column chromatography and ultracentrifugation from the wild-type PRL-R3 strain, induced with l-fucose and two constitutive mutants, 502 and 510. The ratios of the activities of this isomerase on d-arabinose and l-fucose remained constant throughout all purifications. The apparent K(m) of the isomerase from the wild-type strain induced with l-fucose and from the constitutive mutant strains was 5.0 x 10(-2)m for l-fucose and 1.5 x 10(-1)m for d-arabinose. A strain 531 possessing an apparent alteration in the isomerase was isolated from the strain 502. This altered isomerase exhibited a lowered K(m) for d-arabinose.
mesh_terms: D000645:Ammonium Sulfate; D001089:Arabinose / Q000378:metabolism*; D002364:Caseins; D002458:Cell Fractionation; D002499:Centrifugation, Density Gradient; D002845:Chromatography; D003470:Culture Media; D004589:Electrophoresis, Disc; D004754:Enterobacter / Q000187:drug effects / Q000201:enzymology* / Q000378:metabolism; D005643:Fucose / Q000378:metabolism; D005827:Genetics, Microbial; D007535:Isomerases / Q000302:isolation & purification* / Q000378:metabolism; D007536:Isomerism; D008722:Methods; D009153:Mutagens; D009154:Mutation; D009604:Nitrosoguanidines; D011492:Protein Hydrolysates; D013053:Spectrophotometry; D013237:Stereoisomerism; D013395:Sucrose; D014461:Ultracentrifugation; D014994:Xylose / Q000378:metabolism
chemical_list: D002364:Caseins; D003470:Culture Media; D009153:Mutagens; D009604:Nitrosoguanidines; D011492:Protein Hydrolysates; D005643:Fucose; D013395:Sucrose; D014994:Xylose; D001089:Arabinose; D007535:Isomerases; D000645:Ammonium Sulfate