Open AccessGrowth on D-Lyxose of a Mutant Strain of Escherichia coli K12 Using a Novel Isomerase and Enzymes Related to D-Xylose Metabolism
Author(s) -
Fred J. Stevens,
Tai Te Wu
Publication year - 1976
Publication title -
journal of general microbiology/journal of general microbiology
Language(s) - English
Resource type - Journals
eISSN - 2059-9323
pISSN - 0022-1287
DOI - 10.1099/00221287-97-2-257
Subject(s) - isomerase , escherichia coli , biochemistry , mutant , permease , xylose , enzyme , xylose isomerase , strain (injury) , bacteria , biology , structural gene , chemistry , gene , genetics , fermentation , anatomy
Escherichia coli K12 cannot grow on D-lyxose, but a mutant was isolated which can utilize D-lyxose as sole source of carbon and energy for growth. D-Lyxose is transported into the bacteria by the D-xylose permease. The mutant constitutively synthesizes a new isomerase which is not inducible in the parent strain under any of the conditions tested. This enzyme, whose native substrate appears to be D-mannose, fortuitously converts D-lyxose into D-xylulose. Its structural gene is located at around 85 min on the E. coli genetic map, away from other known isomerase genes. D-Xylulose is subsequently catabolized by the enzymes of the normal D-xylose metabolic pathway. D-Mannose isomerase was partially purified and some of its properties were examined.