Growth on D-lyxose of a mutant strain of Escherichia coli K12 using a novel isomerase and enzymes related to D-xylase metabolism.
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.
D002238:Carbohydrate Epimerases / Q000378:metabolism*; D004926:Escherichia coli / Q000254:growth & development / Q000378:metabolism*; D005632:Fructose / Q000378:metabolism; D005796:Genes; D008358:Mannose / Q000378:metabolism; D009154:Mutation; D010429:Pentoses / Q000378:metabolism*; D013237:Stereoisomerism; D014994:Xylose / Q000378:metabolism; D014996:Xylulose / Q000378:metabolism
D010429:Pentoses; D005632:Fructose; D014996:Xylulose; D014994:Xylose; D002238:Carbohydrate Epimerases; D008358:Mannose