title: 3-Ketoglucose reductase of Agrobacterium tumefaciens.
abstract: Two kinds of 3-ketoglucose-reducing enzyme were partially purified from the sonic extract of Agrobacterium tumefaciens IAM 1525 grown on a sucrose-containing medium. Both enzymes have a specific requirement for reduced nicotinamide adenine dinucleotide phosphate (NADPH) as a hydrogen donor and catalyze the reduction of 3-ketoglucose to glucose but do not reduce 3-ketoglucosides such as 3-ketosucrose, 3-ketoglucose-1-phosphate, 3-ketotrehalose, and 3-ketocellobiose. From the requirement and substrate specificity of the enzymes, the name NADPH:3-ketoglucose oxidoreductase (trivial name, 3-ketoglucose reductase) was proposed. By diethylaminoethyl-cellulose column chromatography, two reductases were separated, and the early and late eluted enzymes were designated reductase I and II, respectively. K(m) values of reductase I and II were as follows: for 3-ketoglucose both had an identical value of 2.5 x 10(-5)m, and for NADPH the values were 1.0 x 10(-5)m and 1.5 x 10(-5)m, respectively. Optimal pH values were also identical: pH 4.8 to 5.0 in 10(-2)m phosphate buffer. Intracellular localization of the enzymes is discussed.
mesh_terms: D000429:Alcohol Oxidoreductases / Q000302:isolation & purification / Q000378:metabolism; D000469:Alkaline Phosphatase / Q000378:metabolism; D000645:Ammonium Sulfate; D002384:Catalysis; D002474:Cell-Free System; D011232:Chemical Precipitation; D002848:Chromatography, DEAE-Cellulose; D002854:Chromatography, Paper; D003593:Cytoplasm / Q000201:enzymology; D005947:Glucose / Q000096:biosynthesis; D005959:Glucosidases / Q000378:metabolism; D006026:Glycoside Hydrolases / Q000378:metabolism; D006601:Hexoses / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D009249:NADP / Q000378:metabolism; D009995:Osmosis; D011479:Protamines; D012231:Rhizobium / Q000201:enzymology* / Q000254:growth & development / Q000378:metabolism; D013395:Sucrose / Q000378:metabolism; D014461:Ultracentrifugation
chemical_list: D006601:Hexoses; D011479:Protamines; D009249:NADP; D013395:Sucrose; D000429:Alcohol Oxidoreductases; D000469:Alkaline Phosphatase; D005959:Glucosidases; D006026:Glycoside Hydrolases; D005947:Glucose; D000645:Ammonium Sulfate