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31.
Hiroaki Kamachi Keisuke Tanaka Ryo C. Yanagita Akira Murakami Kazuma Murakami Harukuni Tokuda Nobutaka Suzuki Yu Nakagawa Kazuhiro Irie 《Bioorganic & medicinal chemistry》2013,21(10):2695-2702
We have recently developed a simplified analog of aplysiatoxin (aplog-1) as an activator of protein kinase C (PKC) with anti-proliferative activity like bryostain 1. To identify sites in aplog-1 that could be readily modified to optimize therapeutic performance and to develop a molecular probe for examining the analog’s mode of action, substituent effects on the phenol ring were systematically examined. Whereas hydrophilic acetamido derivatives were less active than aplog-1 in inhibiting cancer cell growth and binding to PKCδ, introduction of hydrophobic bromine and iodine atoms enhanced both biological activities. The anti-proliferative activity was found to correlate closely with molecular hydrophobicity, and maximal activity was observed at a log P value of 4.0–4.5. On the other hand, an induction test with Epstein–Barr virus early antigen demonstrated that these derivatives have less tumor-promoting activity in vitro than aplog-1 regardless of the hydrophobicity of their substituents. These results would facilitate rapid preparation of molecular probes to examine the mechanism of the unique biological activities of aplog-1. 相似文献
32.
Tsukasa Mizuhara Shinya Oishi Hiroaki Ohno Kazuya Shimura Masao Matsuoka Nobutaka Fujii 《Bioorganic & medicinal chemistry》2013,21(7):2079-2087
To investigate the mechanism of action of the potent antiviral compound PD 404182, three novel photoaffinity probes equipped with a biotin or alkyne indicator were designed and synthesized based on previous structure–activity relationship studies. These probes retained the potent anti-HIV activity of the original pyrimidobenzothiazine derivatives. In photoaffinity labeling studies using HIV-1-infected H9 cells (H9IIIB), eight potential proteins were observed to bind PD 404182. 相似文献
33.
Akira Sakurai Yukiharu Sato Keun Hyung Park Nobutaka Takahashi Naohiko Yanagishima Isao Banno 《Bioscience, biotechnology, and biochemistry》2013,77(6):1451-1453
The pullulanase gene (pul) of Klebsiella aerogenes was transferred in vivo to Escherichia coli by using RP4:: Mu cts. The pul gene was expressed in E. coli, although the level of pullulanase activity in E. coli was lower than that in K. aerogenes, and the Pul+ transconjugants were relatively unstable in an unselective medium. Production of pullulanase, which is used to make maltose from starch, was induced in E. coli by pullulan, waxy maize amylopectin, soluble starch and maltose. When the transconjugant cells of E. coli were grown with pullulan or maltose, most pullulanase was produced intracellularly, whereas K. aerogenes produced pullulanase extracellularly. Retransfer of the pulk gene from E. coli to K. aerogenes by conjugation resulted in an increase of the production of extracellular pullulanase. 相似文献
34.
Nobutaka Takahashi Akinori Suzuki Yasuo Kimura Satoshi Miyamoto Saburo Tamura Takashi Mitsui 《Bioscience, biotechnology, and biochemistry》2013,77(9):1115-1122
Piericidin B was isolated from mycellia of Streptomyces mobaraensis besides piericidin A. On the basis of IR, NMR and mass spectral studies together with chemical evidences, its structure was assigned as Id. Its physiological activities are also deescribd. 相似文献
35.
Manh Huynh Vu Tetsu Ando Shigeo Yoshida Nobutaka Takahashi Sadahiro Tatsuki Kazumasa Katagiri 《Bioscience, biotechnology, and biochemistry》2013,77(7):1615-1617
Ferredoxin-nitrite reductase (EC 1.7.7.1), an enzyme which catalyzes the 6-electron reduction of nitrite to ammonia, has been isolated from Spinacia oleracea. The isolated enzyme was homogeneous by disc electrophoresis with polyacrylamide gel. The molecular weight of the enzyme was estimated to be 86,000 by Ultrogel AcA 34 gel filtration. In the oxidized form, the enzyme had absorption maxima at 278, 388 (Soret band), 573 (α band) and 690 nm, indicating that siroheme is directly involved in the catalysis of nitrite reduction. This absorption spectrum was modified by sulfite, hydroxylamine and cyanide. The enzyme exhibited electron paramagnetic resonance signals with g values of 6.9 and 5.2, which are characteristic of a high spin Fe3+ -siroheme in the molecule. These signals disappeared upon the addition of dithionite or nitrite. This isolated enzyme also contained four moles of labile sulfide and 7 g-atoms of iron per 86,000 g of protein. 相似文献
36.
Several 4-thiazolone derivatives were synthesized by condensation of appropriate aryl cyanide and ethyl thioglycolate (or derivative), and factors affecting to the reaction rate are discussed. Keto-enol tautomerization of the 4-thiazolones is briefly discussed. 相似文献
37.
Noboru Murofushi Nobutaka Takahashi Takao Yokota Saburo Tamura 《Bioscience, biotechnology, and biochemistry》2013,77(10):1239-1245
A new gibberellin, gibberellin A20 (GA20), was isolated from immature seeds of morning-glory (Pharbitis nil). Its structure was established as 4aα, 7α-dihydroxy-1β-methyl-8-methylenegibbane-1α, 10β-dicarboxylic acid-1→4a lactone (I) on the basis of its physicochemical analysis as well as chemical evidences. GA20 shows marked growth promoting activities on dwarf maize d2 and d5 but weak activities on d1, rice seedling and dwarf pea. 相似文献
38.
Yukiko Kawanabe Hisakazu Yamane Nobutaka Takahashi Teruko Nakamura 《Bioscience, biotechnology, and biochemistry》2013,77(8):2447-2450
GA3 was identified as a major GA in Neurospora crassa by gas chromatography/selected ion monitoring (GC/SIM) and its content was measured at various stages (0~96 hr after inoculation) of conidial germination and mycelial growth. The GA3 content in the fungus was 190ng/g dry weight at the initial stage and then decreased rapidly; that per liter culture decreased soon after the inoculation, and then increased to 17.6 ng 96 hr after inoculation. The GA3 concentration in the culture medium was around 10?11 m throughout the 96-hr incubation. The physiological role of endogenous GA in Neurospora crassa is also discussed. 相似文献
39.
40.
Noboru Murofushi Yoshio Shigematsu Shigehiro Nagura Nobutaka Takahashi 《Bioscience, biotechnology, and biochemistry》2013,77(9):2305-2311
Steviol (ent-13-hydroxykaur-16-en-19-oic acid)* is metabolized by Gibberella fujikuroi in the presence of inhibitors of gibberellin biosynthesis, such as quaternary ammonium salt-type growth retardants, to afford 7β-Miydroxy- and 6β,7β-dihydroxysteviol, gibberelhns A1, A18, A19, A53 and 7β,13-dihydroxykaurenolide. Steviol acetate (ent-13-acetoxykaur-16-en-19-oic acid) is also metabolized to the 6β,7β-dihydroxy-derivative and to the 13-acetyl derivatives of gibberellins A17 and A20 and steviol methyl ester (methyl ent-13-hydroxykaur-16-en-19-oate) into the monohydroxy-, dihydroxy- and hydroxyoxo-derivatives. These results indicate a low substrate specificity of the enzymes in the fungus and provide a useful preparative methodology of several important plant gibberellins carrying the 13-hydroxyl group. 相似文献