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31.
Localization of arachidonate 12-lipoxygenase in parenchymal cells of porcine anterior pituitary 总被引:2,自引:0,他引:2
N Ueda A Hiroshima K Natsui F Shinjo T Yoshimoto S Yamamoto K Ii K Gerozissis F Dray 《The Journal of biological chemistry》1990,265(4):2311-2316
12-Lipoxygenases oxygenate arachidonic acid producing its 12S-hydroperoxy derivative and are well known as platelet and leukocyte enzymes. When a peroxidase-linked immunoassay of the enzyme according to the avidin-biotin method was applied to the cytosol fractions from various parts of porcine brain, a considerable amount of the enzyme was found in the anterior pituitary. The enzyme level (about 200 ng/mg cytosol protein) corresponded to about 6% of the enzyme content in porcine peripheral leukocytes. Posterior and intermediate lobes showed about one-tenth of the enzyme level of anterior pituitary. Other parts of porcine brain contained the 12-lipoxygenase in amounts below 7 ng/mg cytosol protein. The cytosol fraction (0.7 mg of protein) of anterior pituitary produced 12S-hydroxy-5,8,10,14-eicosatetraenoic acid from 25 microM arachidonic acid in about 34% conversion at 24 degrees C for 5 min, giving a specific enzyme activity about 3 nmol/min/mg protein. Furthermore, various octadecapolyenoic acids were oxygenated almost as fast as the arachidonate 12-oxygenation. When anterior pituitary was investigated immunohistochemically with anti-12-lipoxygenase antibody, most of the immunostained cells were certain parenchymal cells with granules, which were not blood cells. These biochemical and immunohistochemical results provide a good reason for considering that 12-lipoxygenase does play an important role in pituitary function. 相似文献
32.
T Yoshimoto Y Yamamoto T Arakawa H Suzuki S Yamamoto C Yokoyama T Tanabe H Toh 《Biochemical and biophysical research communications》1990,172(3):1230-1235
The cDNA for a 12-lipoxygenase was isolated from cDNA library of human erythroleukemia cells. The cDNA had an open reading frame encoding 663 amino acids with a calculated molecular weight of 75,513. The deduced amino acid sequence of human 12-lipoxygenase exhibited 41.5%, 65.3% and 65.4% identity with human 5-lipoxygenase, human 15-lipoxygenase and porcine 12-lipoxygenase, respectively. Blot hybridization analysis of RNA from human erythroleukemia cells demonstrated a single species (3.1 kb) of mRNA with the cDNA probe for 12-lipoxygenase of these cells, but not with the cDNA for porcine leukocyte enzyme. The cytosol of Escherichia coli transformed with a recombinant pUC19 plasmid oxygenated the position 12 of arachidonic acid. 相似文献
33.
Summary Using aequorin luminescence, we observed a distinct oscillation in Ca2+ levels in the supernatant of the homogenate ofPhysarum plasmodium. Ca2+ oscillation continued for 10–120 minutes, with a period coinciding with that of the contraction rhythm of a plasmodium.Abbreviations EDTA
Ethylenediaminetetraacetic acid
- EGTA
Ethyleneglycol-bis-(-aminoethylether)-N,N-tetraacetic acid
- PIPES
Piperazine-N,N-bis-(2-ethane sulfonic acid)
- DTT
Dithiothreitol
The present work was supported by Grants-in Aid from the Ministry of Education, Science and Culture, Japan. 相似文献
34.
Summary Using bioluminescence of luciferin-luciferase, we showed that ATP leaked out rhythmically from a strand segment ofPhysarum plasmodium made permeable with caffeine-arsenate. With simultaneous measurement of isometric tension rhythm of the strand, it was revealed that the period and phase of oscillation in ATP leakage correspond well with those of tension production. Further, microinjection of luciferin-luciferase into the plasmodial strand indicated that the intracellular luminescence of luciferin-luciferase also oscillates with the same period and in the same phase as the tension rhythm.The free ATP concentration in a homogenate ofPhysarum plasmodium was of the order of 10 M, but if the homogenate was heated in boiling water, the intensity of luminescence suddenly increased 10–100 fold. ATP available for mechanical workin vivo is thus supposed to be at a much lower level than the total average, which was found in the range of 0.2–0.7 mM. 相似文献
35.
Tetsuya Fukui Akio Yoshimoto Mamoru Matsumoto Shunji Hosokawa Terumi Saito Hiroko Nishikawa Kenkichi Tomita 《Archives of microbiology》1976,110(2-3):149-156
The enzyme activity synthesizing poly--hydroxybutyrate (PHB) was mainly localized in the PHB-containing particulate fraction ofZoogloea ramigera I-16-M, when it grew flocculatedly in a medium supplemented with glucose. On the other hand, the enzyme activity remained in the soluble fraction, when the bacterium grew dispersedly in a glucose-starved medium.The soluble PHB synthase activity became associated with the particulate fraction as PHB synthesis was initiated on the addition of glucose to the dispersed culture. Conversely, the enzyme activity was released from the PHB-containing granules to the soluble fraction when the flocculated culture was kept incubated without supplementing the medium with glucose.PHB synthase was also incorporated into the newly formed PHB fraction when partially purified soluble PHB synthase was incubated withd(-)--hydroxybutyryl CoA in vitro.Although attempts to solubilize the particulate enzyme were unsuccessful, and the soluble enzyme became extremely unstable in advanced stages of purification, both PHB synthases had the same strict substrate specificity ford(-)--hydroxybutyryl CoA, and showed the same pH optimum at 7.0.Non-Standard Abbreviations PHB
poly--hydroxybutyrate 相似文献
36.
Minoru Okuma Tanihiro Yoshimoto Shozo Yamamoto 《Prostaglandins & other lipid mediators》1977,14(5):891-896
The effect of human platelet functions of 9,11-dithio analogues of prostaglandin endoperoxide was investigated. Methyl (5z,9α,11α,13e,15S)-9,11-epidithio-15-hydroxyprosta- 5,13-dienoate induced platelet aggregation, while the 9β,11β-epimer was inactive. The platelet aggregation caused by the 9α,11α-dithio analogue was associated with serotonin release from platelets, and was inhibited by methyl ester of prostaglandin I2 (prostacyclin) but not by indomethacin. 相似文献
37.
Toru Sugita Yukari Semi Hiromasa Sawada Yumi Utoyama Yuko Hosomi Eri Yoshimoto Yuki Maehata Hiroyuki Fukuoka Ryutaro Nagata Akio Ohyama 《Molecular breeding : new strategies in plant improvement》2013,31(4):909-920
To facilitate marker-assisted breeding and genetic analyses of pepper (Capsicum annuum), we developed non-redundant 2- or 3-base simple sequence repeat (SSR) markers from enriched C. annuum genomic libraries and from C. annuum cDNA sequences in public databases. The SSR-enriched libraries were constructed using combinations of three restriction enzymes (AluI, HaeIII, and RsaI) and two biotinylated oligonucleotides [b(GA)15 and b(CA)15]. Ultimately, we obtained 1,736 genomic SSR markers and 1,344 cDNA-derived SSR markers from 6,528 clones and 13,003 sequences, respectively. We mapped 597 markers, including 265 of the newly developed SSR markers, onto a linkage map by using doubled-haploid (DH) lines derived from an intraspecific cross of two pure lines of C. annuum (K9-11 × MZC-180). The map, designated as the KL-DH map, consisted of 12 linkage groups. The map covered a genetic distance of 2,028 cM, and the average distance between markers was less than 4 cM. The frame structure of the KL-DH map was compared with the published standard conserved ortholog set II (COSII) map, which was derived from an interspecific F2 population (C. frutescens × C. annuum), by using tomato (Solanum lycopersicum) chromosomal sequences to bridge the two maps. The intraspecific KL-DH map constructed in this study and the interspecific COSII map were similar in map length and marker distribution, suggesting that the KL-DH map covers nearly the whole genome of C. annuum. 相似文献
38.
39.
Nitrogenase catalyzes not only the reduction of N2 to NH3 but also the reduction of C2H2 to C2H4 and H+ ion to H2 gas, etc. The detailed mechanism of the nitrogenase reaction is not clear. We have prepared monoclonal antibodies against Component I nitrogenase of A. vinelandii and examined the effects of antibodies on the nitrogenase reactions. A monoclonal antibody designated MA-1 inhibited C2H2 reduction activity strongly but did not inhibit H2 evolution activity. MA-2, on the contrary, inhibited only H2 evolution activity. MA-8 inhibited both C2H2 reduction and H2 evolution activity to the same extent. 相似文献
40.
Shigehiro Kamoda Naoto Habu Masahiro Samejima Tomotaka Yoshimoto 《Bioscience, biotechnology, and biochemistry》2013,77(10):2757-2761
A novel dioxygenase, lignostilbene-a,β-dioxygenase (LSD), which catalyzes cleavage of the interphenyl double bond of lignin-derived stilbenes, was isolated. Four isozymes of LSD were separated from cell-free extracts of Pseudomonas sp. TMY1009 by ion-exchange chromatography on a DEAE- Toyopearl column. The major isozyme, LSD-I, was purified to electrophoretic homogeneity and characterized.LSD-I cleaved the interphenyl double bond of l,2-bis(4′-hydroxy-3′-methoxyphenyl)ethylene with the optimum pH at 8.5. The Km of LSD-I was 11 μm for the stilbene and 110/iM for oxygen. The molecular weight of LSD-I, which is composed of two identical subunits, was estimated to be 94,000. LSD-I contained 1 g atom of iron per 1 mol of enzyme protein. 相似文献