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41.
42.
Jan T. Keltjens Henny J. Rozie Godfried D. Vogels 《Archives of biochemistry and biophysics》1984,229(2):532-537
During purification procedures and upon aerobic heating with alkali a green-yellow degradation fluorescent product (GY) was formed from 5,10-methenyl-5,6,7,8-tetrahydromethanopterin, an intermediate in the reduction of CO2 to methane [J. T. Keltjens, L. Daniels, H. G. Janssen, and G. D. Vogels (1983)Eur. J. Biochem.130, 545–552]. GY was suggested to be a 6-(1-oxo)-7,8-dihydropterin. On the basis of the spectral properties and the results of degradation studies, it was now shown that the structure of GY is 6-acetyl-7-methyl-7,8-dihydropterin. This structure was confirmed by synthesis of the compound and other reference substances. 相似文献
43.
Peter van der Meijden Chris van der Drift Godfried D. Vogels 《Archives of microbiology》1984,138(4):360-364
The conversion of methanol by cell-free extracts of the acetogenic bacterium Eubacterium limosum was studied. Incubation of mixed cell-free extracts of both E. limosum and Methanobacterium formicicum resulted in methane formation from methanol in the presence of ATP and 2-mercaptoethanesulfonic acid. The separate extracts were not able to perform this reaction. Addition of ferredoxin obtained from Methanosarcina barkeri to the mixed extracts resulted in increased methane formation. The enzyme, responsible for methanol binding in cell-free extract of E. limosum, was inactivated by FAD under N2 and exhibited maximal activity under an atmosphere of H2. This enzyme contains a firmly bound cobalamin which was methylated by methanol in the presence of ATP. It was demethylated in the presence of methylcobalamin: coenzyme M methyltransferase obtained from M. barkeri under concomitant formation of methylated coenzyme M. These properties are similar to those of methanol: 5-hydroxybenzimidazolylcobamide methyltransferase from M. barkeri. It was proposed that methylotrophic acetogens and methylotrophic methanogens use similar enzymes in the first step of methanol conversion.Abbreviations HS-CoM
2-mercaptoethanesulfonic acid
- CH3S-CoM
2-(methylthio)ethanesulfonic acid
- BrES
2-bromoethanesulfonic acid
- TES
N-tris(hydroxymethyl)-methyl-2-aminoethanesulfonic acid
- MT1
methanol: 5-hydroxybenzimidazolylcobamide methyltransferase
- MT2
methylcobalamin
- HS-CoM
methyltransferase
- DMBI
5,6-dimethylbenzimidazole and HBI, 5-hydroxybenzimidazole, are -ligands of corrinoids
- (S-CoM)2
2,2-dithiodiethanesulfonic acid 相似文献
44.
H. de Verneuil B. Grandchamp Chantal Foubert Dominique Weil Cong Van N'Guyen Marie-Sylvie Gross Shigeru Sassa Y. Nordmann 《Human genetics》1984,66(2-3):202-205
Summary A specific enzyme immunoassay of uroporphyrinogen decarboxylase was developed and applied to the detection of the human enzyme in man-rodent somatic cell hybrids. This method allowed to assign the gene for uroporphyrinogen decarboxylase to human chromosome 1. 相似文献
45.
46.
Acetate,methanol and carbon dioxide as substrates for growth of Methanosarcina barkeri 总被引:10,自引:0,他引:10
T. J. Hutten H. C. M. Bongaerts C. van der Drift G. D. Vogels 《Antonie van Leeuwenhoek》1980,46(6):601-610
Methanosarcina barkeri grows in defined media with acetate, methanol or carbon dioxide as carbon sources. Methanol is used for methanogenesis at a 5 times higher rate as compared with the other substrates. M. barkeri can use the substrates simultaneously, but due to acidification or alkalification of the medium during growth on methanol or acetate, respectively, growth and methanogenesis may stop before the substrates are exhausted. Growth and methanogenesis on methanol or acetate are inhibited by the presence of an excess of H2; the inhibition is abolished by the addition of carbon dioxide, which probably serves as an essential source of cell carbon, in the absence of which methano-genesis ceases. 相似文献
47.
Dominique Weil Nguyen Van-Cong Catherine Finaz R. Rebourcet Chantal Cochet J. de Grouchy J. Frézal 《Human genetics》1977,36(2):205-211
Summary 22 independent man-hamster (HGPRT–) hybrids using male human cells with balanced reciprocal translocation t(X;2)(p22;q32) were analysed for human genes localized on chromosome 2 (IDHS, MDHS), on chromosome X (PGK, GAL, G6PD) and for the different chromosomes in relation with the balanced reciprocal translocation (chr.2, chr.2q–, chr.Xp+).The following results were obtained:The chromosomes 2 and 2q– are absent in the 22 hybrids.In 9 hybrids, the absence of MDHS in spite of the presence of the chromosome Xp+ indicates that the gene for MDHS is not localized on this chromosome (or that the gene for MDHS is not on the segment 2q32-2qter translocated on X).In 14 hybrids, the three markers of X (PGK, GAL, G6PD) and IDHS are expressed in the presence of the chromosome Xp+. This result indicates that the genes for these markers are on Xp+ or that the genes PGK, GAL, G6PD are on X without the Xp22-Xter segment, translocated on the chr.2, and that the gene for IDHS is on the 2q32-2qter segment translocated on X.In 8 hybrids, in the absence of the intact chromosome Xp+, the higher percentage of the presence of G6PD (7 hybrids) and the lower percentage of the presence of IDHS (3 hybrids) are explained by the fact that these hybrids selected in HAT medium had to retain a segment of Xp+ bearing the human gene HGPRT. G6PD appeared very close to HGPRT and IDHS very distant from HGPRT.The study of the different correlations between the presence and the absence of these four markers on Xp+ in the different hybrids indicates the following order on the chromosome Xp+ from p to q: IDHs — PGK — GAL — G6PD.
Groupe INSERM: Directeur J. Frézal
Groupe CNRS, ER, 149: Directeur J. de Grouchy 相似文献
Groupe INSERM: Directeur J. Frézal
Groupe CNRS, ER, 149: Directeur J. de Grouchy 相似文献
48.
49.
Characterization of exoglucanase and synergistic hydrolysis of cellulose in Clostridium stercorarium
Abstract A cellobiohydrolase component was isolated from an anaerobic thermophilic cellulolytic bacterium, Clostridium stercorarium . When acting alone, the enzyme showed minimal activity towards ordered substrates such as cellulose and filter paper but it has been shown to attack phosphoric-acid swollen cellulose giving cellobiose as principal product. When recombined with endoglucanase it did allow an extensive hydrolysis demonstrating a marked synergism in the action of those two components; the addition of β-glucosidase resulted in a further increase in activity. 相似文献
50.
Jan T. Keltjens William B. Whitman C. Gerda Caerteling Annette M. van Kooten Ralph S. Wolfe Godfried D. Vogels 《Biochemical and biophysical research communications》1982,108(2):495-503
2-Mercaptoethanesulfonic acid (coenzyme M), or a derivative of it, and a yellow chromophore, known as the nickel-containing tetrapyrrole factor F430, occur in the prosthetic group of methylcoenzyme M reductase in an equimolar amount, and bound to each other; this enzyme catalyzes the final step of methane production. The prosthetic group, which is called coenzyme MF430, was isolated from the purified enzyme and was extracted from cells. The presence of coenzyme M was confirmed by a bioassay using Methanobrevibacter ruminantium and by the use of chemical and physicochemical analyses. 相似文献