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41.
H Oritani Y Deyashiki T Nakayama A Hara H Sawada K Matsuura Y Bunai I Ohya 《Archives of biochemistry and biophysics》1992,292(2):539-547
A pyrazole-sensitive carbonyl reductase from pig lung was purified to homogeneity by electrophoretic criteria. Chemical cross-linking study suggested that the native enzyme is a tetramer with a Mr of 103,000, consisting of apparent identical subunits of Mr 24,000. The enzyme reduced aliphatic and aromatic carbonyl compounds with NADPH as a preferable cofactor to NADH and catalyzed the oxidation of secondary alcohols and the aldehyde dismutation in the presence of NAD(P)+. Immunohistochemical study with the antibodies against the enzyme revealed that the enzyme was localized in the ciliated cells, nonciliated bronchiolar cells, Type II alveolar pneumocytes, and the epithelial cells of the ducts of the bronchial glands in the pig lung. In addition to the properties and distribution, the pig lung enzyme was immunochemically similar to the pulmonary enzymes in the guinea pig and mouse. However, the pig enzyme showed the following unusual features. (1) The enzyme exhibited an equatorial specificity in the reduction of 3-ketosteroids; the 4-pro-S hydrogen of NADPH was transferred to the carbonyl carbon atom of 5 alpha- and 5 beta-androstanes, and the respective reduced products were identified as 3 beta- and 3 alpha-hydroxysteroids. (2) Although the NADPH-linked reduction of carbonyl compounds apparently obeyed the Michaelis-Menten kinetics at pH 6.0, the double-reciprocal plots of the velocity vs concentrations of the carbonyl substrates were convex at pH higher than 6.5. The Hill coefficients and [S]0.5 values for the substrates decreased as the pH for reaction increased. The results suggest that the pig enzyme exhibits negative cooperativity with respect to the carbonyl substrates and that the hydrogen ion acts as an allosteric effector abolishing the negative interaction. 相似文献
42.
Motohiro Matsuura Shinji Saito Yoshikazu Hirai Haruki Okamura 《European journal of biochemistry》2003,270(19):4016-4025
Production of nitric oxide (NO) in response to bacterial lipopolysaccharide (LPS) was investigated using cultures of mouse peritoneal exudate cells (PEC) and the macrophage cell line RAW264.7. In the presence of anti-(interferon-gamma) (IFN-gamma), NO production was markedly suppressed in the PEC culture but not in the RAW264.7 culture. In the PEC culture, LPS induced both IFN-gamma production and activation of IFN response factor-1, which leads to the gene expression of inducible NO synthase, but neither was induced in the culture of RAW264.7 cells. In addition to anti-(IFN-gamma), antibodies against interleukin (IL)-12 and IL-18 showed a suppressive effect on LPS-induced NO production in the PEC culture, and these antibodies in synergy showed strong suppression. Stimulation of the PEC culture with IL-12 or IL-18 induced production of IFN-gamma and NO, and these cytokines, in combination, exhibited marked synergism. Stimulation of the culture with IFN-gamma induced production of NO, but not IL-12. The macrophage population in the PEC, prepared as adherent cells, responded well to LPS for IL-12 production, but weakly for production of IFN-gamma and NO. The macrophages also responded well to IFN-gamma for NO production. For production of IFN-gamma by stimulation with LPS or IL-12 + IL-18, nonadherent cells were required in the PEC culture. Considering these results overall, the indirect pathway, through the production of intermediates (such as IFN-gamma-inducing cytokines and IFN-gamma) by the cooperation of macrophages with nonadherent cells, was revealed to play the main role in the LPS-induced NO production pathway, as opposed to the direct pathway requiring only a macrophage population. 相似文献
43.
Kenzo Kumamoto Satomi Ebara Fumihiko Fukuda Tadao Matsuura 《Cell and tissue research》1995,280(2):253-258
Grandry corpuscles in the oral mucosa of the upper bill of the duck were immunohistochemically studied using antisera against calcitonin gene-related peptide (CGRP), galanin, methionine-enkephalin, neuropeptide Y (NPY), somatostatin, substance P (SP) and vasoactive intestinal peptide (VIP). Grandry corpuscles in the lamina propria selectively showed only SP-like immunoreactivity. Herbst corpuscles distributed near Grandry corpuscles were negative to all antisera applied. Although immunoreactive products in the Grandry corpuscles were found as granules in the peripheral cytoplasm of the Grandry cell, the axon terminals and satellite cells exhibited no reactivity. In pre-embedding electron-microscopic sections, SP-like immunoreactive products visualized with 3,3-diaminobezidine were localized in the granules of Grandry cells, but no labeling was observed in the cytoplasmic matrix or cell organelles. Electron-immunocytochemical labeling with colloidal gold by the post-embedding method clearly demonstrated that the SP antigen was localized only in the granules. It is presumed that Grandry cells have a secretory function. However, the function and the method of release of the SP contained in the observed granules remains obscure. Some CGRP-, NPY-, SP- and VIP-like-immunoreactive nerve fibers with varicosities associated with blood vessels and nerve fiber bundles of various sizes were observed in the lamina propria, but no such fibers penetrated into the intraepitherial layer. Nerve fibers positive for SP and VIP were also found in the interlobular connective tissue of the palatine glands. Some SP-positive neurons were detected in the vicinity of the palatine glands. 相似文献
44.
45.
S Kanegasaki Y Kojima M Matsuura J Y Homma A Yamamoto Y Kumazawa K Tanamoto T Yasuda T Tsumita M Imoto 《European journal of biochemistry》1984,143(2):237-242
Lipid A analogues were chemically synthesized based on the model structure recently revised, and biological activities of the analogues were tested. The analogue, (beta-1,6)-linked glucosamine disaccharide carrying ester-bound 3-hydroxytetradecanoic acids at 3 and 3' position of reducing and nonreducing glucosamine in addition to amide-bound 3-hydroxytetradecanoic acids and glycosidic-linked and ester-linked phosphate groups, showed much stronger activities for mediator inducing and immunomodulating as well as endotoxic activities than those exhibited by the previously synthesized analogues based on the old model. Among the activities tested, induction of interferon and tumor necrosis factor as well as mitogenicity, adjuvanticity and pyrogenicity were, however, not expressed so strongly as natural lipid A used as controls. In contrast, the analogue exhibited comparable activities to those of control lipid A in the test of lethal toxicity to mice and gelating activity of Limulus amebocyte lysate. Other synthetic analogues carrying a phosphate group showed comparable, slightly stronger or weaker activities depending on the test, but nonphosphorylated analogue exhibited no apparent or only very weak activities. 相似文献
46.
Biological activities of chemically synthesized analogues of the nonreducing sugar moiety of lipid A 总被引:12,自引:0,他引:12
M Matsuura Y Kojima J Y Homma Y Kubota A Yamamoto M Kiso A Hasegawa 《FEBS letters》1984,167(2):226-230
Adriamycin-Fe3+ complex catalyzes the formation of hydroxyl radical from hydrogen peroxide but the DNA-adriamycin-iron ternary complex is much more effective. 11-Deoxyadriamycin, which shows no spectral evidence of complex formation with iron, was ineffective. The generation of hydroxyl radical by adriamycin-Fe3+ complex in the presence of DNA correlates with its ability to cleave DNA. Hydroxyl radicals are thus implicated as the reactive oxygen species involved in the DNA damage caused by the adriamycin-Fe3+ complex. 相似文献
47.
Summary Sixteen patients with unusual heteromorphisms involving alterations of the length and/or position of centromeric heterochromatin are described. Family studies showed that the heteromorphisms were present in other relatives and segregated in the expected 1:1 ratio. There was a significantly greater frequency of unusual heteromorphisms among Orientals than in other races studied. 相似文献
48.
1. Four stereochemical isomers of tetrahydrobiopterin, i.e., 6-L-erythro-, 6-D-erythro-, 6-L-threo-, or 6-D-threo-1,2-dihydroxypropyltetrahydropterin, have been synthesized and used as cofactors for tyrosine hydroxylase (EC 1.14.18.-) purified from the soluble fraction of bovine adrenal medulla. The L-erythro- (the putative natural cofactor) and D-threo isomers showed a striking similarity in their cofactor activities for tyrosine hydroxylase; the remaining two isomeric tetrahydrobiopterins, D-erythro and L-threo isomers, also had very similar cofactor characteristics. 2. The Km values of the L-erythro and D-threo isomers as cofactor were found to be dependent on their concentrations. When their concentrations were below 100 muM, the Km values of the L-erythro and D-threo isomers were fairly low (about 20 muM). However, the Km values were markedly higher (about 150 muM) at concentrations above 100 muM. The same kinetic behavior was also observed with the tetrahydrobiopterin prepared from a natural source (bullfrog). In contrast, the Km value of the L-threo or D-erythro isomer was found to be independent of the concentration and remained constant throughout the concentration examined. 3. The Km values of tyrosine did not show much difference (from 20 muM to 30 muM) with respect to the structure of the four isomeric cofactors. At high concentrations tyrosine inhibited the enzymatic reaction with any one of the four tetrahydrobiopterin cofactors. 4. Oxygen at high concentrations was also inhibitory with any one of the four stereochemical isomers as cofactor. Approximate Km values for oxygen with the tetrahydrobiopterins as cofactor were 1-5%. 5. In contrast to the four isomers of tetrahydrobiopterin, when 6-methyltetrahydropterin or 6,7-dimethyltetrahydropterin was used as cofactor tyrosine or oxygen did no inhibit the enzymatic reaction at high concentrations, and the Km values toward the pterin cofactor, tyrosine, and oxygen were significantly higher than the Km values with the tetrahydrobiopterins as cofactor. 相似文献
49.
The shift of the carotenoid absorption spectrum induced by illumination and valinomycin-K+ addition was investigated in membrane structures with different characteristics and opposite sidednesses isolated from Rhodopseudomonas sphaeroides. Right-side-out membrane structures were prepared by isotonic lysozyme-EDTA treatment of the cells (spheroplasts) and by hypotonic treatment of spheroplasts (spheroplast membrane vesicles). Inside-out membrane structures ("chromatophores") were obtained by treating spheroplast membrane vesicles by French press or sonication. The membrane structures with either sidedness showed the same light-induced change of the "red shift" type. However, the absorbance change by K+ addition in the presence of valinomycin in the right-side-out membrane structures were opposite to that in the inverted vesicles, "blue shift" in the former and "red shift" in the latter. The carotenoid absorbance change was linear to membrane potential, calculated from the concentration of KCl added, with a reference on the cytoplasmic side, through positive and negative ranges. 相似文献
50.
Proteoliposomes were reconstituted from detergent-solubilized pigment.protein complexes of chromatophores of Rhodopseudomonas sphaeroides and soybean phospholipids. The reconstituted vesicles showed a photooxidation of reaction center bacteriochlorophyll and a light-induced spectral shift of carotenoid to longer wave-lengths. The red shift similar to that in intact cells or chromatophores, indicates the generation of local fields in the membrane of proteoliposomes. When inside-positive membrane potential was induced by adding valinomycin and potassium salt, a shift of carotenoid spectrum to shorter wavelengths was observed. Therefore, the reconstituted vesicles, at least in the major part of population, produced the light-induced local field in the same direction as in intact cells, which is inside negative. Sidedness of the membrane structure and the direction of electric field formation in reconstituted vesicles were opposite to those in chromatophores (inside-out vesicles. 相似文献