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1.
Phosphorylation and Inactivation of Brain Glycogen Synthase by a Multifunctional Calmodulin-Dependent Protein Kinase 总被引:1,自引:1,他引:0
Nobuhiro Inoue Takafumi Iwasa Kohji Fukunaga Yasuhiko Matsukado Eishichi Miyamoto 《Journal of neurochemistry》1987,48(3):981-988
Glycogen synthase was partially purified from canine brain to about 70% purity. The purified enzyme showed differences from the properties of the skeletal muscle enzyme with respect to molecular weights of the holoenzyme and subunit and phosphopeptide mapping. The multifunctional calmodulin-dependent protein kinase from the brain phosphorylated brain glycogen synthase with concomitant inactivation of the enzyme. Although about 1.3 mol of phosphate/mol subunit was maximally incorporated into glycogen synthase, 0.4 mol of phosphate/mol subunit was sufficient for the maximal inactivation of the enzyme. The results indicate that brain glycogen synthase is regulated in a calmodulin-dependent manner similarly to the skeletal muscle enzyme, but that the brain enzyme is different from the skeletal muscle enzyme. 相似文献
2.
Changes in Crassulacean Acid Metabolism of Kalanchoe blossfeldiana by Different Nitrogen Sources 总被引:2,自引:0,他引:2
Kalanchoe blossfeldiana Poelln. cv. Hikan (a Crassulacean acidmetabolism (CAM) plant) was grown in pots containing soil for6 months and then cultured in nutrient solution containing 10mM nitrate or ammonium as a sole nitrogen source for 2 or 3months, under a long-day (16 h) condition. Plant growth was better in the nitrate medium. Leaves of thenitrate-grown plants showed greater diurnal fluctuations intitratable acidity and malate content than those of the ammonium-grownplants. The diurnal patterns in CO2 exchange of nitrate-grownplants were basically similar for both groups, but the amountof net CO2 uptake at night was twice as large in the nitrate-grownplants. The leaves of the nitrate-grown plants had 1.3 to 2.5times higher activities of phosphoenolpyruvate carboxylase (PEPC),phosphofructokinase (PFK) and NAD glycelaldehyde-3-phosphatedehydrogenase (G3PDH). These results indicate that K. blossfeldianagrown in nitrate medium showed more CAM activity than thosein ammonium medium. (Received August 13, 1987; Accepted February 22, 1988) 相似文献
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Yohichi Kamata Shunji Kozaki Takafumi Nagai Genji Sakaguchi 《FEMS microbiology letters》1985,26(3):305-309
Abstract Five monoclonal antibodies (MCA; E–8–2, 9–1, 11–2, 12–4, and 13–1) against Clostridium botulinum type E derivative toxin were prepared. Their ELISA titers were higher than or equivalent to that of conventional polyclonal antibody. Three of them (E-8–2, 12–4, and 13–1) possessed the neutralizing activity comparable to that of polyclonal antibody. The results of binding-competition experiments indicated that the monoclonal antibodies bound to different sites on the type E toxin molecule. Immunoblotting analyses demonstrated that E-8–2, 9–1, and 11–2 react to fragment I (heavy chain) of the toxin. By use of these monoclonal antibodies, it may be possible to scrutinize the structure-function relationship of botulinum toxins and cross reactions between type E and F toxins. 相似文献
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N-hydroxy-2-naphthylamine (NOH-2NA). an active metabolite of human occupational bladder carcinogens, induced, in V79 Chinese hamster cells. chromosomal aberrations which were suppressed in the presence of catalase and/or superoxide dismutase. The induction of the aberrations was more efficient in a more basic pH in parallel with the generation of hydrogen peroxide from NOH-2NA. The possible role of the oxidation product of NOH-2NA in the induction of the aberrations is discussed. 相似文献
5.
Junko Komura Ikumi Tamai Mizuho Senmaru Tetsuya Terasaki Yoshimichi Sai Akira Tsuji 《Journal of neurochemistry》1996,67(1):330-335
Abstract: The characteristics of β-alanine transport at the blood-brain barrier were studied by using primary cultured bovine brain capillary endothelial cells. Kinetic analysis of the β-[3 H]alanine transport indicated that the transporter for β-alanine functions with Kt of 25.3 ± 2.5 µ M and J max of 6.90 ± 0.48 nmol/30 min/mg of protein in the brain capillary endothelial cells. β-[3 H]Alanine uptake is mediated by an active transporter, because metabolic inhibitors (2,4-dinitrophenol and NaN3 ) and low temperature reduced the uptake significantly. Furthermore, the uptake of β-[3 H]alanine required Na+ and Cl− in the external medium. Stoichiometric analysis of the transport demonstrated that two sodium ions and one chloride ion are associated with one β-alanine molecule. The Na+ and Cl− -dependent uptake of β-[3 H]alanine was stimulated by a valinomycin-induced inside-negative K+ -diffusion potential. β-Amino acids (β-alanine, taurine, and hypotaurine) inhibited strongly the uptake of β-[3 H]alanine, whereas α- and γ-amino acids had little or no inhibitory effect. In ATP-depleted cells, the uptake of β-[3 H]alanine was stimulated by preloading of β-alanine or taurine but not l -leucine. These results show that β-alanine is taken up by brain capillary endothelial cells, via the secondary active transport mechanism that is common to β-amino acids. 相似文献
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Seiji Ichida Tetsuyuki Wada Masahiro Sekiguchi Hiroyuki Kishino Yuko Okazaki Takafumi Akimoto 《Neurochemical research》1993,18(11):1137-1144
Characteristics of specific125I-omega-conotoxin (-CgTX) binding were systematically investigated in crude membranes from rat whole brain. Kd and Bmax Values for the binding were 49.7 pM and 181.5 fmol/mg of protein, respectively. The effects of various types of Ca channel antagonists on the binding were investigated. Dynorphin A (1–13), in particular, specifically inhibited125I--CgTX binding, but not that of [3H](+)PN200-110. Spider venom fromPlectreurys tristes did not specifically inhibit specific binding of125I--CgTX, because the venom also inhibited the binding of [3H](+)PN200-110 to a similar degree. The amount of specific binding of125I--CgTX was less in the cerebellum than that in any other area of whole brain. The cross-linker disuccinimidyl suberate did not label with125I--CgTX and its binding sites in rat whole brain, although it did in chick whole brain, which was used as a positive control. These findings suggested that dynorphine A (1–13) was a selective blocker of -CgTX-sensitive Ca channels in crude membranes from rat whole brain and that -CgTX-sensitive Ca channels were mainly present a rat brain except cerebellum. 相似文献
8.
Takafumi Tadano Hiroki Otani Masanori Taira Igor B. Dawid 《Genesis (New York, N.Y. : 2000)》1993,14(3):204-211
Mesoderm development in Xenopus laevis depends on inductive cell interactions mediated by diffusible molecules. The mesoderm inducer activin is capable of redirecting the development of animal explants both morphologically and biochemically. We have studied the induction of four regulatory genes, Mix. 1, goosecoid (gsc), Xlim-1 and Xbra in such explants by activin, and the influence of other factors on this induction. Activin induction of gsc is strongly enhanced by dorsalization of the embryo by LiCl, while expression of the other genes is only slightly enhanced. The protein synthesis inhibitor cycloheximide (CHX) inhibits the activin-dependent induction of Xbra partially, while induction of Mix. 1 and Xlim- 1 is essentially unaffected. In contrast, gsc shows strong superinduction in the presence of activin and CHX, and can be induced in animal explants by CHX alone. Induction and superinduction by CHX have previously been observed for immediate early genes in a variety of systems, notably for the activation of c-fos expression by serum stimulation, but have not been reported in early amphibian embryos. © 1993Wiley-Liss, Inc. 相似文献
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