Kyoto University · 공학
타카시 와타나베 교수의 연구실은 목재 화학과 생물학적 분해 메커니즘을 중심으로 한 고도화된 생체분해 연구를 수행하고 있습니다. 특히 리그닌과 다당류가 결합한 복합체(LCC)의 결합 구조를 규명하기 위해 DDQ 산화법을 응용한 분석 기법을 개발하였으며, 리그닌 분해에 관여하는 효소 및 산화 반응 메커니즘을 밝혀내는 데 초점을 맞추고 있습니다. 또한, 효소의 기질 특이성과 반응 메커니즘, 예를 들어 β-글루쿠조니다제의 전이글루코실화 반응과 같은 생화학적 반응의 기작 연구도 진행하고 있습니다.
표시된 성과는 수집된 데이터 기준으로 산출되며, 일부 차이가 있을 수 있습니다.
Beta-glucosidase was purified from a crude cellulase preparation from Aspergillus niger by affinity chromatography on a methacrylamide-N-methylene-bis-methacrylamide copolymer bearing cellobiamine. The purified enzyme was a dimer with an isoelectric point of 4.0. The molecular mass of the enzyme was estimated to be 240 kDa by gel-permeation chromatography. The enzyme hydrolyzed specifically beta-glucosidic bonds and catalyzed transglucosylation of the beta-glucosyl group of cellobiose to yield 4
Ceriporiopsis subvermispora is capable of decomposing lignin without penetration of enzymes into wood cell walls. To elucidate the mechanism of lignolysis at a site far from enzymes, peroxidation of low molecular mass compounds produced by this fungus was analyzed. C. subvermispora produced free 9,12-octadecadienoic, 9-octadecenoic, 11-octadecenoic, hexadecanoic and octadecanoic acids, predominantly at an early stage of cultivation on wood meal cultures. In prolonged cultivation period after 2 w
Borylative radical cyclization of benzo[3,4]cyclodec-3-ene-1,5-diynes to provide 5-borylated 6,7,8,9-tetrahydrobenzo[a]azulenes has been developed. The experimental results suggest that the reaction proceeds by a radical chain mechanism, in which di-tert-butyl hyponitrite (TBHN) works as a good radical initiator to form boryl radicals from N-heterocyclic carbene-boranes (NHC-boranes). The present reaction is a rare model that illustrates addition of boryl radicals to alkynes.
Journal Article Evidence for an Ester Linkage between Lignin and Glucuronic Acid in Lignin–Carbohydrate Complexes by DDQ-Oxidation Get access Takashi Watanabe, Takashi Watanabe Section of Wood Chemistry, Wood Research Institute, Kyoto University, Gokasho, Uji, Kyoto 611, Japan Search for other works by this author on: Oxford Academic Google Scholar Tetsuo Koshijima Tetsuo Koshijima Section of Wood Chemistry, Wood Research Institute, Kyoto University, Gokasho, Uji, Kyoto 611, Japan Search for oth
Lignin-carbohydrate complexes (LCC; nor-C-1-M, com-C-1-A) isolated from normal and compression woods of Pinus densiflora were hydrolyzed with two types of cellulase preparations, and the hydrolyzates formed were fractionated by adsorption chromatography on polyvinyl gel into water-soluble materials and LCC fragments. To elucidate the binding sites between the lignin and carbohydrate, the cellulase-degraded LCC fragments were subjected to acetylation, and then oxidation with 2, 3-dichloro-5, 6-di
The magnetic susceptibilities of single crystals of NiSO 4 ·7H 2 O and α-NiSO 4 ·6H 2 O have been measured in the temperature range between liquid helium and room temperatures. The magnetic susceptibility of these salts at low temperatures shows that the level splittings in the ground of each salt are not so small. The seventh water molecule in the heptahydrate salt forms a hydrogen bond and the hexahydrate salt has not a hydrogen bond. The signs of the isotropic Weiss constant of both salts whi
Acid-catalysed degradation of wood in toluene–MeOH yields the lignin monomers homovanillyl aldehyde dimethyl acetal and homosyringaldehyde dimethyl acetal selectively.
In enzymatic saccharification of lignocellulosics, the access of the enzymes to exposed cellulose surfaces is a key initial step in triggering hydrolysis. However, knowledge of the structure-hydrolyzability relationship of the pretreated biomass is still limited. Here we used fluorescent-labeled recombinant carbohydrate-binding modules (CBMs) from Clostridium josui as specific markers for crystalline cellulose (CjCBM3) and non-crystalline cellulose (CjCBM28) to analyze the complex surfaces of wo
