Plausible phosphoenolpyruvate binding site revealed by 2.6 Å structure of Mn2+-bound phosphoenolpyruvate carboxylase from Escherichia coli11The coordinates and structure factors have been deposited in the Protein Data Bank (accession number 1QB4).

AbstractWe have determined the crystal structure of Mn2+-bound Escherichia coli phosphoenolpyruvate carboxylase (PEPC) using X-ray diffraction at 2.6 Å resolution, and specified the location of enzyme-bound Mn2+, which is essential for catalytic activity. The electron density map reveals that Mn2+ is bound to the side chain oxygens of Glu-506 and Asp-543, and located at the top of the α/β barrel in PEPC. The coordination sphere of Mn2+ observed in E. coli PEPC is similar to that of Mn2+ found in the pyruvate kinase structure. The model study of Mn2+-bound PEPC complexed with phosphoenolpyruvate (PEP) reveals that the side chains of Arg-396, Arg-581 and Arg-713 could interact with PEP

ダイチョウキンホスホエノールピルビンサンカルボキシラーゼノカッセイニタイオウスルコンホーメーションノタヨウセイトソガイインシノコウゾウトクイセイニツイテ

京都大学0048新制・論文博士理学博士乙第3268号論理博第566号新制||理||244(附属図書館)5165UT51-52-L85(主査)教授 香月 裕彦, 教授 波多野 博行, 教授 川出 由己学位規則第5条第2項該当Kyoto UniversityDA

TEMPO‐Oxidized Cellulose Nanofibers as Pseudocatalysts for in Situ and on‐Demand Hydrogen Generation via Aluminum Powder/Pure Water Reactions at a Temperature below 50 °C

Cellulose nanofibers (CNFs) prepared via 2,2,6,6‐tetramethylpiperidine‐1‐oxyl (TEMPO)‐mediated oxidation of the C6 primary hydroxyls of native cellulose to carboxylates are used as pseudocatalysts for enhancing the aluminum powder/pure water reactions. The Al powder/pure water reaction is a stepwise reaction. It starts from hydration of the outmost native Al2O3 thin layer and then the reaction of the inner metallic Al with water. At lower temperatures ( 11) is dynamically generated, and as a result, the native Al2O3 thin layer dissolves rapidly via the reaction with OH− ions. The OH− ions function also as catalysts, accelerating the reaction of metallic Al with water. Al powders (2–200 μm) react promptly and a nearly 100% Al/H2 conversion is obtained at the reaction temperature below 50 °C

Localized gastric amyloidosis differentiated histologically from scirrhous gastric cancer using endoscopic mucosal resection: a case report

<p>Abstract</p> <p>Introduction</p> <p>Amyloidosis most often manifests as a systemic involvement of multiple tissues and organs, and an amyloidal deposit confined to the stomach is extremely rare. It is sometimes difficult to provide a definitive diagnosis of localized gastric amyloidosis by biopsy specimen and diagnosis of amyloidosis in some cases has been finalized only after surgical resection of the stomach.</p> <p>Case presentation</p> <p>A 76-year-old Japanese woman with epigastric discomfort underwent an esophagogastroduodenoscopy procedure. The esophagogastroduodenoscopy revealed gastric wall thickening, suggesting scirrhous gastric carcinoma, at the greater curvature from the upper to the lower part of the gastric corpus. A biopsy specimen revealed amyloid deposits in the submucosal layer with no malignant findings. We resected a representative portion of the lesion by endoscopic mucosal resection using the strip biopsy method to obtain sufficient tissue specimens, and then conducted a detailed histological evaluation of the samples. The resected specimens revealed deposition of amyloidal materials in the gastric mucosa and submucosa without any malignant findings. Congo red staining results were positive for amyloidal protein and exhibited green birefringence under polarized light. Congo red staining with prior potassium permanganate incubation confirmed the light chain (AL) amyloid protein type. Based on these results, gastric malignancy, systemic amyloidosis and amyloid deposits induced by inflammatory disease were excluded and this lesion was consequently diagnosed as localized gastric amyloidosis. Our patient was an older woman and there were no findings relative to an increase in gastrointestinal symptoms or anemia, so no further treatment was performed. She continued to be in good condition without any finding of disease progression six years after verification of our diagnosis.</p> <p>Conclusions</p> <p>We report an unusual case of primary amyloidosis of the stomach resembling scirrhous gastric carcinoma. This case of localized gastric amyloidosis was differentiated from scirrhous gastric cancer after performing endoscopic mucosal resection without an invasive surgical resection, as endoscopic mucosal resection provided sufficient tissue specimens from the lesion to make an accurate histological evaluation.</p