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Chromatographia - Recently, we developed a sensitive and accurate quantification method for short-chain peptides using dual functional-group derivatization. Sensitive and accurate quantification... 相似文献
23.
Takumi Nakajima Ken Takano Hiromu Maeda Dr. Yohei Ogiwara Prof. Dr. Norio Sakai 《化学:亚洲杂志》2021,16(24):4103-4107
The results of this study show that disilathiane is an effective mediator in the synthesis of alkyl aryl sulfides with disulfides and alkyl carboxylates. Mechanistic studies suggest that disilathiane promotes cleavage of the sulfur–sulfur bond of disulfides to generate thiosilane as a key intermediate. Diselenides were also applicable to this transformation to produce the corresponding selenides. 相似文献
24.
Yohei Saito Atsushi Mizokami Kouji Izumi Renato Naito Masuo Goto Kyoko Nakagawa-Goto 《Molecules (Basel, Switzerland)》2021,26(9)
α-Trifluoromethyl chalcones were prepared and evaluated for their antiproliferative activities against androgen-independent prostate cancer cell lines as well as five additional types of human tumor cell lines. The most potent chalcone 5 showed superior antitumor activity in vivo with both oral and intraperitoneal administration at 3 mg/kg. Cell-based mechanism of action studies demonstrated that 5 induced cell accumulation at sub-G1 and G2/M phases without interfering with microtubule polymerization. Furthermore, several cancer cell growth-related proteins were identified by using chalcone 5 as a bait for the affinity purification of binding proteins. 相似文献
25.
Serine‐Selective Aerobic Cleavage of Peptides and a Protein Using a Water‐Soluble Copper–Organoradical Conjugate 下载免费PDF全文
Yohei Seki Dr. Kana Tanabe Dr. Daisuke Sasaki Dr. Youhei Sohma Dr. Kounosuke Oisaki Prof. Dr. Motomu Kanai 《Angewandte Chemie (International ed. in English)》2014,53(25):6501-6505
The site‐specific cleavage of peptide bonds is an important chemical modification of biologically relevant macromolecules. The reaction is not only used for routine structural determination of peptides, but is also a potential artificial modulator of protein function. Realizing the substrate scope beyond the conventional chemical or enzymatic cleavage of peptide bonds is, however, a formidable challenge. Here we report a serine‐selective peptide‐cleavage protocol that proceeds at room temperature and near neutral pH value, through mild aerobic oxidation promoted by a water‐soluble copper–organoradical conjugate. The method is applicable to the site‐selective cleavage of polypeptides that possess various functional groups. Peptides comprising D ‐amino acids or sensitive disulfide pairs are competent substrates. The system is extendable to the site‐selective cleavage of a native protein, ubiquitin, which comprises more than 70 amino acid residues. 相似文献
26.
In this Review, we summarize the current state of the art in late‐transition‐metal‐catalyzed reactions of acyl fluorides, covering both their synthesis and further transformations. In organic reactions, the relationship between stability and reactivity of the starting substrates is usually characterized by a trade‐off. Yet, acyl fluorides display a very good balance between these properties, which is mostly due to their moderate electrophilicity. Thus, acyl fluorides (RCOF) can be used as versatile building blocks in transition‐metal‐catalyzed reactions, for example, as an “RCO” source in acyl coupling reactions, as an “R” source in decarbonylative coupling reactions, and as an “F” source in fluorination reactions. Starting from the cleavage of the acyl C?F bond in acyl fluorides, various transformations are accessible, including C?C, C?H, C?B, and C?F bond‐forming reactions that are catalyzed by transition‐metal catalysts that contain the Group 9–11 metals Co, Rh, Ir, Ni, Pd, or Cu. 相似文献
27.
Naoki Kise Yosei Takenaga Yohei Ishikawa Yoichi Morikami Toshihiko Sakurai 《Tetrahedron letters》2012,53(15):1940-1945
The reductive coupling of N-methoxycarbonyl lactams with benzophenone by Zn-TiCl4 in THF gave cross-coupled products as cyclic α-diphenylidene-N-methoxycarbonylamines and ring-opening α,α-diphenyl-α-hydroxy-ω-(N-methoxycarbonyl)amino ketones selectively depending on the reduction conditions. The reductive coupling of N-methoxycarbonyl lactams with 9-fluorenone by Zn-TiCl4 gave cyclic α-(9H-fluoren-9-ylidene)-N-methoxycarbonylamines preferentially irrespective to the conditions. 相似文献
28.
Yohei Morinishi 《Journal of computational physics》2010,229(2):276-300
The form of convective terms for compressible flow equations is discussed in the same way as for an incompressible one by Morinishi et al. [Y. Morinishi, T.S. Lund, O.V. Vasilyev, P. Moin, Fully conservative higher order finite difference schemes for incompressible flow, J. Comput. Phys. 124 (1998) 90], and fully conservative finite difference schemes suitable for shock-free unsteady compressible flow simulations are proposed. Commutable divergence, advective, and skew-symmetric forms of convective terms are defined by including the temporal derivative term for compressible flow. These forms are analytically equivalent if the continuity is satisfied, and the skew-symmetric form is secondary conservative without the aid of the continuity, while the divergence form is primary conservative. The relations between the present and existing quasi-skew-symmetric forms are also revealed. Commutable fully discrete finite difference schemes of convection are then derived in a staggered grid system, and they are fully conservative provided that the corresponding discrete continuity is satisfied. In addition, a semi-discrete convection scheme suitable for compact finite difference is presented based on the skew-symmetric form. The conservation properties of the present schemes are demonstrated numerically in a three-dimensional periodic inviscid flow. The proposed fully discrete fully conservative second-order accurate scheme is also used to perform the DNS of compressible isotropic turbulence and the simulation of open cavity flow. 相似文献
29.
Deepti A. Salvi Giovanna M. Aita Diana Robert Victor Bazan 《Applied biochemistry and biotechnology》2010,161(1-8):67-74
A new pretreatment technology using dilute ammonium hydroxide was evaluated for ethanol production on sorghum. Sorghum fibers, ammonia, and water at a ratio of 1:0.14:8 were heated to 160 °C and held for 1 h under 140–160 psi pressure. Approximately, 44% lignin and 35% hemicellulose were removed during the process. Hydrolysis of untreated and dilute ammonia pretreated fibers was carried out at 10% dry solids at an enzyme concentration of 60 FPU Spezyme CP and 64 CBU Novozyme 188/g glucan. Cellulose digestibility was higher (84%) for ammonia pretreated sorghum as compared to untreated sorghum (38%). Fermentations with Saccharomyces cerevisiae D5A resulted in 24 g ethanol /100 g dry biomass for dilute ammonia pretreated sorghum and 9 g ethanol /100 g dry biomass for untreated sorghum. 相似文献
30.
The relationship among the Wigner crystal, charge ordering, and the Mott insulator is studied by the path-integral renormalization group method in two-dimensional systems with long-range Coulomb interaction. In contrast to the insensitivity of the Hartree-Fock results, the stability of the solid drastically decreases with the decrease in the lattice commensurability. The transition to liquid occurs at the electron gas parameter r(s) approximately 2 for the filling n=1/2, showing a large reduction from r(s) approximately 35 in the continuum limit. A correct account of quantum fluctuations is crucial to understanding the charge-order stability generally observed only at simple fractional fillings and the nature of quantum liquids away from them. 相似文献