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Tomokazu Ito Jumpei Iimori Sayuri Takayama Akihito Moriyama Ayako Yamauchi Hisashi Hemmi Tohru Yoshimura 《Journal of bacteriology》2013,195(24):5439-5449
Escherichia coli YggS is a member of the highly conserved uncharacterized protein family that binds pyridoxal 5′-phosphate (PLP). To assist with the functional assignment of the YggS family, in vivo and in vitro analyses were performed using a yggS-deficient E. coli strain (ΔyggS) and a purified form of YggS, respectively. In the stationary phase, the ΔyggS strain exhibited a completely different intracellular pool of amino acids and produced a significant amount of l-Val in the culture medium. The log-phase ΔyggS strain accumulated 2-ketobutyrate, its aminated compound 2-aminobutyrate, and, to a lesser extent, l-Val. It also exhibited a 1.3- to 2.6-fold increase in the levels of Ile and Val metabolic enzymes. The fact that similar phenotypes were induced in wild-type E. coli by the exogenous addition of 2-ketobutyrate and 2-aminobutyrate indicates that the 2 compounds contribute to the ΔyggS phenotypes. We showed that the initial cause of the keto acid imbalance was the reduced availability of coenzyme A (CoA); supplementation with pantothenate, which is a CoA precursor, fully reversed phenotypes conferred by the yggS mutation. The plasmid-borne expression of YggS and orthologs from Bacillus subtilis, Saccharomyces cerevisiae, and humans fully rescued the ΔyggS phenotypes. Expression of a mutant YggS lacking PLP-binding ability, however, did not reverse the ΔyggS phenotypes. These results demonstrate for the first time that YggS controls Ile and Val metabolism by modulating 2-ketobutyrate and CoA availability. Its function depends on PLP, and it is highly conserved in a wide range species, from bacteria to humans. 相似文献
43.
Yasuji Minoda Hisashi Yamagata Tohru Kodama 《Bioscience, biotechnology, and biochemistry》2013,77(7):1829-1830
Strains producing higher levels of cellulolytic enzymes were selected from among 520 strains of plant pathogenic fungi, Fusarium species, and F. oxysporum strain SUF850 was found to be the best producer. When strain SUF850 was cultured using one of three polysaccharides, Avicel, carboxy- methyl cellulose (CMC) or xylan, as a carbon source, the culture filtrate contained degrading activi- ties toward all three substrates, i.e., irrespective of the carbon source used. From the culture filtrate of Avicel-grown cells, four distinct enzymes were purified to homogeneity, as judged on SDS-PAGE. They were designated as CMCase I, CMCase II, /Miitrophenyl-β-d-cellobiosidase and xylanase, and the characteristics of the individual enzymes were examined and compared. 相似文献
44.
Fatty livers were produced by feeding rats an amino acid imbalanced diet containing 8% of casein supplemented with 0.3% of DL-methionine, and the oxidative phosphorylation of liver mitochondria and homogenates was examined. In contrast to choline deficiency, the mitochondria and the homogenates of fatty liver resulting from such an amino acid imbalance showed almost normal P:O ratio. However, the response to an osmotic treatment of liver mitochondria of rats fed the amino acid imbalanced diet was different from that of normal rats. 相似文献
45.
Shohei Sakuda Akira Isogai Tsukasa Makita Shogo Matsumoto Koshi Koseki Hisashi Kodama 《Bioscience, biotechnology, and biochemistry》2013,77(12):3251-3259
The structures of allosamidin (1) and methylallosamidin (2), novel insect chitinase inhibitors, were elucidated as 1 and 2 by acid hydrolysis experiments and analyses of 2d-NMR spectra. They are unique basic pseudotrisaccharides consisting of 2-acetamido-2-deoxy-d-allose (N-acetyl-d- allosamine) and a novel aminocyclitol derivative (3), termed allosamizoline. 相似文献
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Studies were made on the incorporation of 14C of acetate-1-14C into the lipids of the liver and carcass, and changes in the concentrations of nucleotides, citric acid, and free fatty acids in the liver, using rats fed diets consisting of starch and casein, or starch and corn oil, at different ratios. Lipogenesis was stimulated with an increase in the content of starch both in the starch-casein and starch-corn oil diets. There was a rapid drop in lipogenesis in rats fed the diet with a little increment in the content of corn oil. Lipogenesis decreased gradually with an increment in the content of casein in the starch-casein diet. A positive correlation was found between lipogenesis and the level of ATP in the liver. The concentration of citric acid decreased with an increase in lipogenesis in the liver. Changes in dietary composition did not produce any significant alteration in the concentration of free fatty acids in the liver. 相似文献
49.
Hisashi Ashida Kana Tanigawa Masashi Kiyohara Toshihiko Katoh Takane Katayama 《Bioscience, biotechnology, and biochemistry》2013,77(11):2030-2039
ABSTRACTSialidases catalyze the removal of terminal sialic acid from various complex carbohydrates. In the gastrointestinal tract, sialic acid is commonly found in the sugar chain of mucin, and many enteric commensals use mucin as a nutrient source. We previously identified two different sialidase genes in Bifidobacterium bifidum, and one was cloned and expressed as an extracellular protein designated as exo-α-sialidase SiaBb2. The other exo-α-sialidase gene (siabb1) from the same bifidobacterium encodes an extracellular protein (SiaBb1) consisting of 1795 amino acids with a molecular mass of 189 kDa. SiaBb1 possesses a catalytic domain that classifies this enzyme as a glycoside hydrolase family 33 member. SiaBb1 preferentially hydrolyzes α2,3-linked sialic acid over α2,6-linked sialic acid from sialoglycan, which is the same as SiaBb2. However, SiaBb1 has an SGNH hydrolase domain with sialate-O-acetylesterase activity and an N-terminal signal sequence and C-terminal transmembrane region. SiaBb1 is the first bifunctional sialidase identified with esterase activity.Abbreviations: GalNAc: N-acetyl-D-galactosamine; Fuc: L-fucose; Gal: D-galactose 相似文献
50.
Yuji Shimizu Mio Nakazato Takaharu Sekita Koichiro Kadota Kazuhiko Arima Hironori Yamasaki Hisashi Goto Satoshi Shirahama Noboru Takamura Kiyoshi Aoyagi Takahiro Maeda 《Journal of physiological anthropology》2013,32(1):19