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Biomedical subjects

S Fukui

Publications and source records attributed to S Fukui.

At least 361 records · Page 20Linked to original sources
PubMed1973

3-Ketoglucose reductase of Agrobacterium tumefaciens.

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.

Alcohol Oxidoreductases↗
PubMed1973

Glucose-1-phosphate-negative mutant of Agrobacterium tumefaciens.

Glucose-1-phosphate-negative mutants that are unable to grow in a synthetic medium containing glucose-1-phosphate (G-1-P) as a sole carbon source were isolated by treatment of Agrobacterium tumefaciens IAM 1525 with N-methyl-N'-nitro-N-nitrosoguanidine. All of the enzymes involved in G-1-P metabolism (glucoside-3-dehydrogenase, 3-ketoglucose-1-phosphate-degrading enzyme, alpha-glucosidase, and phosphatases) were detected in the sonic extract prepared from resting cells of one of the mutants, strain M-24, in approximately equal levels to those in the parent strain. Resting cells of the mutant oxidized G-1-P to 3-ketoglucose-1-phosphate (3KG-1-P), the first product in G-1-P metabolism by the bacterium, with little subsequent degradation, whereas the parent showed further degradation of G-1-P via 3KG-1-P. Glucoside-3-dehydrogenase catalyzing 3-ketoglucoside formation was readily released from cells by osmotic shock, whereas the 3KG-1-P-degrading enzyme was not released. Thus, the former and the latter enzymes might be at different intracellular loci, such as periplasm and cytoplasm, respectively. It is suggested that the mutant strain M-24 is a G-1-P-negative mutant deficient in a 3KG-1-P transport system located on the cytoplasmic membrane.

Acid Phosphatase↗
PubMed1972

Isolation of morphological mutants of Agrobacterium tumefaciens.

Morphological mutants were isolated from a wild strain of Agrobacterium tumefaciens at a high frequency by treatment with a nitrosoguanidine. Seventeen of the 20 mutants isolated were temperature-sensitive. At 27 C, the mutant cells were rod-shaped and at 37 C, spherical or branched, whereas the wild-type cells were rod-shaped at both temperatures.

Culture Media↗