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31.
Transformation of leukotriene A4 methyl ester to leukotriene C4 monomethyl ester by cytosolic rat glutathione transferases 总被引:6,自引:0,他引:6
Bengt Mannervik Helgi Jensson Per Ålin Lars Örning Sven Hammarström 《FEBS letters》1984,175(2):289-293
Six major basic cytosolic glutathione transferases from rat liver catalyzed the conversion of leukotriene A4 methyl ester to the corresponding leukotriene C4 monomethyl ester. Glutathione transferase 4-4, the most active among these enzymes, had a Vmax of 615 nmol X min-1 X mg protein-1 at 30 degrees C in the presence of 5 mM glutathione. It was followed in efficiency by transferase 3-4 which had a Vmax of 160 nmol X min-1 X mg-1 under the same conditions. Transferases 1-1, 1-2, 2-2 and 3-3 had at least 30 times lower Vmax values than transferase 4-4. 相似文献
32.
Soil microfungi in three Swedish coniferous forests 总被引:4,自引:0,他引:4
Microfungi were isolated with the soil washing technique from five different soil horizons in three podzolic coniferous forests in Sweden. Totally 126 species were identified of which 45 were found at two and 24 were found at three sites. The most common genera were Mortierella and Penicillium . Other genera isolated in high frequences were Oidiodendron, Tolypocladium, Trichoderma and Verticillium . Pronounced differences in species composition were found between the soil layers, while great similarities were shown in identical soil layers at different sites. 相似文献
33.
Leukotriene A: stereochemistry and enzymatic conversion to leukotriene B 总被引:13,自引:0,他引:13
Olof Rådmark Curt Malmsten Bengt Samuelsson David A. Clark Giichi Goto Anthony Marfat E.J. Corey 《Biochemical and biophysical research communications》1980,92(3):954-961
Leukotriene A was assigned the structure 5(S)--5,6-oxido-7,9--eicosatetraenoic acid by the enzymatic conversion of a synthetic product of known stereochemistry into the naturally occurring isomer of 5(S),12(R)-dihydroxy-6,8,10,14-eicosatetraenoic acid in human polymorphonuclear leukocytes. 相似文献
34.
David A. Clark Giichi Goto Anthony Marfat E.J. Corey Sven Hammarström Bengt Samuelsson 《Biochemical and biophysical research communications》1980,94(4):1133-1139
A slow reacting substance, produced by murine mastocytoma cells, has been shown to have the structure 5(S)-hydroxy-6(R)--glutathionyl-7,9,11- leukotriene C, previously referred to as leukotriene C-2) by ultraviolet spectroscopy, amino acid analyses, lipoxygenase conversion and comparisions with a synthetic compound of known structure and stereochemistry. 相似文献
35.
Michael K. Bach John R. Brashler Sven Hammarström Bengt Samuelsson 《Biochemical and biophysical research communications》1980,93(4):1121-1126
Slow reacting substance (SRS), produced by rat peritoneal mononuclear cells after stimulation with ionophore A23187, consists of two main components (Bach, M.K. et al. (1979) J. Immunol. 122, 160–165). One of these components was recently identified as leukotriene C-1. The other component has now been identified as leukotriene D. 相似文献
36.
Lars-Åke Fransson Anders Malmström Ingrid Sjöberg Thomas N. Huckerby 《Carbohydrate research》1980,80(1):131-145
Heparin, heparan sulphate, and various derivatives thereof have been oxidised with periodate at pH 3.0 and 4° and at pH 7.0 and 37°. Whereas oxidation under the latter conditions destroys all of the nonsulphated uronic acids, treatment with periodate at low pH and temperature causes selective oxidation of uronic acid residues. The reactivity of uronic acid residues depends on the nature of neighbouring 2-amino-2-deoxyglucose residues. d-Glucuronic acid residues are susceptible to oxidation when flanked by N-acetylated amino sugars, but resistant when adjacent residues are either unsubstituted or N-sulphated. L-Iduronic acid residues in their natural environment (2-deoxy-2-sulphoamino-d-glucose) are resistant to oxidation, whereas removal of N-sulphate groups renders a portion of these residues periodate-sensitive. Oxidised uronic acid residues in heparin-related glycans may be cleaved by alkali, producing a series of oligosaccharide fragments. Thus, periodate oxidation-alkaline elimination provides an additional method for the controlled degradation of heparin. 相似文献
37.
Bovine aortic chondroitin sulphate- and dermatan sulphate-containing proteoglycans. Isolation, fractionation and chemical characterization. 总被引:2,自引:2,他引:0
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1. Guanidinium chloride (4M) in the presence of proteinase inhibitors extracted 90% of bovine aorta galactosaminoglycans as proteoglycans that were subsequently purified by ion-exchange and gel chromatography. 2. Fractionation of the calcium salts of the purified proteoglycans with increasing concentration of ethanol yielded fractions PG-25 (28%), PG-35 (45%) and PG-50 (37%). 3. Fraction PG-50 contained proteochondroitin 6-sulphate, whereas fractions PG-25 and PG-35 were proteodermatan sulphates of greatly different carbohydrate composition; the molar proportions of L-iduronate-N-acetylgalactosamine 4-sulphate, D-glucuronate-N-acetyl-galactosamine 4-sulphate and D-glucuronate-N-acetylgalactosamine 6-sulphate were 75: 18 :7 in fraction PG-25 and 14 :46 :40 in fraction PG-35. 4. The presence of alternating or mixed sequences with L-iduronate- and D-glucuronate-containing repeating disaccharides was indicated by the formation of tetrasaccharides after chondroitinase AC digestion (single L-iduronate residues) and by the release of fragments containing four or five consecutive D-glucuronate-N-acetylgalactosamine repeats after periodate oxidation and alkaline elimination. 5. The amino acid compositions of fractions PG-25 and PG-35 were similar and markedly different from that of fraction PG-50, which also contained more side chains. 相似文献
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Plasma levels of prolactin and FSH in free-living Pied flycatchers were studied in relation to breeding stage, clutch size and diurnal variations. In the female, the concentration of prolactin started to increase during the egg-laying and reached maximal values at the end of the incubation period. After hatching prolactin levels decreased. Male Pied flycatchers showed an increase in plasma levels of prolactin at the time when they returned to their home-territories, i.e. at the end of the incubation period. Males still occupying secondary territories at this time had low levels of prolactin. In the males, as in the females, plasma levels of prolactin decreased after hatching.
Male Pied flycatchers showed at all times higher plasma levels of FSH than did females. In both sexes FSH levels were high during the early part of the breeding season and started to decrease after the egg-laying period. After hatching time plasma levels of FSH were below the sensitivity of the assay. No differences in FSH were found between males occupying secondary territories and males in home-territories.
In incubating females FSH, but not prolactin, showed a distinct unimodal daily cycle.
No differences were found in plasma levels of prolactin and FSH between females incubating different sized clutches. 相似文献
Male Pied flycatchers showed at all times higher plasma levels of FSH than did females. In both sexes FSH levels were high during the early part of the breeding season and started to decrease after the egg-laying period. After hatching time plasma levels of FSH were below the sensitivity of the assay. No differences in FSH were found between males occupying secondary territories and males in home-territories.
In incubating females FSH, but not prolactin, showed a distinct unimodal daily cycle.
No differences were found in plasma levels of prolactin and FSH between females incubating different sized clutches. 相似文献