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61.
Hiromi Kitano Yasushi Maeda Kanae Furukawa Takahiro Yamamoto Rie Izumida Seiichi Matsugo 《Photochemistry and photobiology》1995,62(5):809-812
Abstract— -Modification of an enzyme, α-chymotrypsin, was examined by using a water-soluble photo-Fenton reagent. By photoirradiation of the enzyme with the reagent, which can occupy a binding site of the enzyme, a tryptophan residue in the vicinity of the active site was oxidized to N -formylkynurenine. Concurrently, the catalytic properties of the enzyme were largely changed: the K m was increased and the k cat was decreased. The decrease in k cat for a specific amide substrate was the most significant among the esters and amides examined. The water-soluble photo-Fenton reagent would be useful to chemically modify relatively limited regions in biomolecules. 相似文献
62.
Kanae Hayashi 《Journal of polymer science. Part A, Polymer chemistry》1980,18(1):179-189
Bulk polymerization of isobutyl vinyl ether was studied at 25°C in a wide dose rate range, 8.2-277 rad/sec by γ rays and 8.8 × 103-2.2 × 105 rad/sec by electron beams. At low dose rate, 8.2-277 rad/sec, only the radical polymerization took place. At high dose rate exceeding 8.8 × 103 rad/sec, cationic polymerization was found to occur in addition to the radical polymerization. DP n of the product at high dose rate was 9-10. Further drying of the monomer increased Rp, and molecular weight of the product formed by cationic mechanism also increased. 相似文献
63.
Designer chiral quaternary ammonium bifluoride 1 has been prepared, and both its catalytic and its chiral efficiency have been clearly demonstrated by achieving the first catalytic asymmetric nitroaldol reaction of silyl nitronate with aldehydes. For instance, the reaction of trimethylsilyl nitronate 2 (R(1) = Me) with benzaldehyde (R(2) = Ph) in THF in the presence of (S,S)-1 (2 mol %) proceeded smoothly at -78 degrees C, giving the corresponding nitroaldol adduct 3 (R(1) = Me, R(2) = Ph) in 92% isolated yield (anti/syn = 92:8) with 95% ee (anti isomer). The method was found to be successfully applicable to other aromatic aldehydes and silyl nitronates, and a high level of anti selectivity and enantiomeric excess was constantly observed. This finding should lead to the further development of fluoride ion-catalyzed asymmetric carbon-carbon bond-forming reactions. 相似文献
64.
Kanae Hayashi Michhinori Tachibana Seizo Okamura 《Journal of polymer science. Part A, Polymer chemistry》1980,18(11):3297-3305
Bulk polymerization of chloroprene was studied at 25°C in a wide does rate range. Variations of the rate of polymerization (Rp) and molecular weight as a function of does rate were essentially the same as those in several monomers that are capab;e of radical and cationic polymerizations. The polymerization proceeds with radical mechanism at low dose rate ans with radical and cationic mechanism concurrently at high dose rate. The number-average molecular weight of the high-dose-rate was ca. 2400. Microstructure of the polymers was mainly of trans-1,4 unit with small fraction of cis-1,4 and 3,4-vinyl unit. Fractions of the vinyl unit and the inverted unit in trans-1,4 sequence which increased at high does rate inflected the change of dominant mechanism of polymerization. 相似文献
65.
Kanae Hayashi Michinori Tachibana Seizo Okamura 《Journal of polymer science. Part A, Polymer chemistry》1980,18(9):2785-2791
Effects of electron beam irradiation on liquid polybutadiene in n-hexane solution were studied at ?10°C. With irradiation, crosslinking of the polymer and loss of double bond by cyclization took place at the same time. These reactions were retarded by the addition of DPPH or triethylamine which indicated that both radical and cationic mechanisms contributed to this system. 相似文献
66.
Dr. Yoshiyuki Manabe Yuki Iizuka Ryuku Yamamoto Keita Ito Kanae Hatano Dr. Kazuya Kabayama Prof. Koichi Fukase 《Angewandte Chemie (International ed. in English)》2023,62(30):e202304779
Antibody dynamics on membranes, such as endocytosis and clustering, are vital in determining antibody functions. In this study, we demonstrated that glycan conjugation can modulate antibody dynamics through the glycan–lectin interaction to regulate its potency. The anti-HER2 antibody, an anti-breast-cancer antibody, was conjugated with galactose-containing N-glycan, and its internalization was suppressed by interaction with galectin-3, leading to enhanced complement-dependent cytotoxic (CDC) activity. This glycan–antibody conjugate is proposed as a new approach to modulate antibody activity and may provide an alternative strategy for redeveloping antibody drugs that do not exhibit sufficient activity. 相似文献