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  • 11
    Electronic Resource
    Electronic Resource
    Purification and characterization of the NADH-dependent (S)-specific 3-oxobutyryl-CoA reductase from Clostridium tyrobutyricum (1995)
    Springer
    Archives of microbiology 163 (1995), S. 310-312 
    Details
    ISSN: 1432-072X
    Keywords: 3-Oxobutyryl-CoA reductase ; Ethyl (S)-3-hydroxybutyrate ; Clostridium tyrobutyricum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract An NADH-dependent (S)-specific 3-oxobutyryl-CoA reductase from Clostridium tyrobutyricum was purified 15-fold with a yield of 46%. It was homogeneous by gel electrophoresis after three chromatographic steps. The apparent molecular mass was estimated by column chromatography to be 240 kDa. SDS-gel electrophoresis revealed the presence of 33 kDa subunits. Substrates of the enzyme were ethyl and methyl 3-oxobutyrate, 3-oxobutyryl-N-acetylcysteamine thioester, and 3-oxobutyryl coenzyme A. The specific activities were 340 and 10 U (mg protein)-1 for the reduction of 3-oxobutyryl coenzyme A and ethyl 3-oxobutyrate, respectively; the Michaelis constants were 300 μM and 300 mM, respectively. The identity of 12 N-terminal amino acid residues was determined. The ezmyme was used in a preparative reduction of substrate, yielding ethyl (S)-3-hydroxybutyrate (〉99% enantiomeric excess).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00393386
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  • 12
    Electronic Resource
    Electronic Resource
    On the occurrence of enoate reductase and 2-oxo-carboxylate reductase in clostridia and some observations on the amino acid fermentation by Peptostreptococcus anaerobius (1983)
    Springer
    Archives of microbiology 135 (1983), S. 51-57 
    Details
    ISSN: 1432-072X
    Keywords: Amino acid fermentation ; Clostridia ; Enoate reductase ; 2-Oxo-carboxylate reductase ; Peptostreptococcus anaerobius ; Stickland reaction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Enoate reductase present in Clostridium kluyveri and Clostridium spec. La 1 could be detected in three strains of C. tyrobutyricum and ten clostridia belonging to the groups of proteolytic and saccharolytic or proteolytic species, respectively. In C. pasteurianum, C. butyricum and C. propionicum enoate reductase could not be found even after growth on (E)-2-butenoate. A 2-oxo-carboxylate reductase was present in rather low activities in the non-proteolytic clostridia which produce enoate reductase. High activities (up to 10 U/mg protein) of 2-oxo-carboxylate reductase were found in six of ten proteolytic clostridia. The substrate specificies of the enoate reductase and the 2-oxocarboxylate reductases from the proteolytic clostridia were determined with different α,β-unsaturated carboxylates (enoates) and 2-oxo-carboxylates, respectively. Enoates as well as 2-oxo-carboxylates are intermediates of the pathway by which amino acids are degraded. An explanation is offered for the long known but not understood fact that in the Stickland reaction isoleucine always acts as an electron donor and leucine and phenylalanine can be electron acceptors as well as donors. Peptostreptococus anaerobius converting some amino acids to the same products as C. sporogenes did this also with the intermediates which were found for the reductive deamination of amino acids in C. sporogenes, however, in crude extracts reduction of enoates occurred only in an activated form.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00419482
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  • 13
    Electronic Resource
    Electronic Resource
    On a reversible molybdenum-containing aldehyde oxidoreductase from Clostridium formicoaceticum (1993)
    Springer
    Archives of microbiology 159 (1993), S. 244-249 
    Details
    ISSN: 1432-072X
    Keywords: Aldehyde oxidoreductase ; Clostridium formicoaceticum ; Molybdenum containing ; Substrate specificity ; Tungsten-containing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Clostridium formicoaceticum grown in the presence of 1 mM molybdate and about 1.5×10-5 mM tungsten (present in the 5 g yeast extract/l of the growth medium) forms two reversible aldehyde oxidoreductases in an activity ratio of about 45:55. The fraction of 45% does not bind to the octyl-Sepharose column, whereas the 55% aldehyde oxidoreductase binds to this column. From cells grown on a synthetic medium without the addition of tungstate only about 2% of the aldehyde oxidoreductase of the crude extract binds to octyl-Sepharose. The enzyme not binding to octyl-Sepharose has been purified as judged by electrophoresis. It is pure after about 50 fold enrichment. According to SDS gel electrophoresis the enzyme consists of identical 100 kD subunits. Based on gel chromatography it seems to be a trimer. Per subunit 0.6 molybdenum, 7 iron, 6.6 acid labile sulphur, about 0.1 pterin-6-carboxylic and 〈0.05 tungsten have been found. The first 13 amino acids from the amino end show no similarity with the W-containing aldehyde oxidoreductase from the same bacterium. With reduced tetramethylviologen (E0=−550 mV) the new molybdenum containing enzyme can reduce various aliphatic and aromatic acids to aldehydes. The pH optimum is at 6.0. For the dehydrogenation of butyraldehyde a rather broad pH region from pH 6 to 10 shows almost no variation of rate. From 15 different aldehydes acetaldehyde exhibits the highest rate. The Km value for butanal is 0.002 and for propionate 7.0 mM. Compared with the tungsten enzyme the molybdenum enzyme is only moderately oxygen-sensitive.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00248479
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  • 14
    Electronic Resource
    Electronic Resource
    The activities of hydrogenase and enoate reductase in two Clostridium species, their interrelationship and dependence on growth conditions (1980)
    Springer
    Archives of microbiology 127 (1980), S. 279-287 
    Details
    ISSN: 1432-072X
    Keywords: Clostridium sp. La 1 ; Carbon sources ; Clostridium kluyveri ; Hydrogenase ; Enoate reductase ; Relationship of enoate reductase and hydrogenase ; Iron ; Sulfur
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The enzyme activities of Clostridium La 1 and Clostridium kluyveri involved in the stereospecific hydrogenation of α,β-unsaturated carbonyl compounds with hydrogen gas were measured. In C. La 1 the specific activities of hydrogenase and enoate reductase depended heavily on the growth phase and the composition of the medium. During growth in batch cultures on 70 mM crotonate the specific activity of hydrogenase increased and then dropped to about 10% of its maximum value, whereas the activity of enoate reductase reached its maximum in cells of the stationary phase. Under certain conditions during growth the activity ratio hydrogenase: enoate reductase changed from 120 to 1. Thus, the rate limiting enzyme for the hydrogenation can be either the hydrogenase or the enoate reductase, depending on the growth conditions of the cells. The specific activities of ferredoxin-NAD reductase and butyryl-CoA dehydrogenase increased 3-4-fold during growth on crotonate. By turbidostatic experiments it was shown that at constant input of high crotonate concentrations (200 mM) the enoate reductase activity was almost completely suppressed; it increased steadily with decreasing crotonate down to an input concentration of 35 mM. Glucose as carbon source led to high hydrogenase and negligible enoate reductase activities. The latter could be induced by changing the carbon source of the medium from glucose to crotonate. Tetracycline inhibited the formation of enoate reductase. A series of other carbon sources was tested. They can be divided into ones which result in high hydrogenase and rather low enoate reductase activities and others which cause the reverse effect. When the Fe2+ concentration in crotonate medium was growth limiting, cells with relatively high hydrogenase activity and very low enoate reductase activity in the stationary phase were obtained. At Fe2+ concentrations above 3·10-7 M enoate reductase increased and hydrogenase activity reached its minimum. The ratio of activities changes by a factor of about 200. In a similar way the dependence of enzyme activities on the concentration of sulfate was studied. In batch cultures of Clostridium kluyveri a similar opposite time course of enoate reductase and hydrogenase was found. The possible physiological significance of this behavior is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00427205
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  • 15
    Electronic Resource
    Electronic Resource
    Utilization of (E)-2-butenoate (Crotonate) by Clostridium kluyveri and some other Clostridium species (1980)
    Springer
    Archives of microbiology 125 (1980), S. 159-165 
    Details
    ISSN: 1432-072X
    Keywords: Clostridium kluyveri ; Crotonate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Clostridium La 1 obtained from a Clostridium kluyveri culture was compared with a typical C. kluyvery strain (DSM 555). The former grows on crotonate and is unable to use ethanol-acetate as carbon sources. The latter grows on crotonate only after long adaptation periods. Resting cells of both strains show also pronounced differences in the fermentation of crotonate. This holds even for C. kluyveri grown on crotonate. Besides several other differences the most striking is that there is no hybridization between the DNA of both strains. Crotonate seems not to be a very special carbon source since C. butyricum and C. pasteurianum grow on crotonate medium supplemented by peptone and yeast extract.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00403214
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  • 16
    Electronic Resource
    Electronic Resource
    The role of tungstate and/or molybdate in the formation of aldehyde oxidoreductase in Clostridium thermoaceticum and other acetogens; immunological distances of such enzymes (1992)
    Springer
    Archives of microbiology 158 (1992), S. 81-84 
    Details
    ISSN: 1432-072X
    Keywords: Acetogens ; Aldehyde oxidoreductase ; Immunological distance ; Molybdate ; Tungstate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Besides Clostridium thermoaceticum and C. formicoaceticum other resting acetogenic clostridia such as C. aceticum and C. thermoautotrophicum and to a lesser extent non-clostridial acetogens such as Butyribacterium methylotrophicum and Eubacterium limosum were able to reduce propionate to propanol at the expense of carbon monoxide or formate. Methylviologen usually increased the reduction rate. Ten μM molybdate in the growth medium decreased this capability for C. thermoaceticum but increased it or had no effect for the other organisms. Ten μM tungstate in the growth medium increased the aldehyde oxidoreductase activity in all organisms. Crude extracts of C. thermoaceticum cells grown in the presence of 10 μM or 1 mM molybdate showed by ELISA the same or even a 4 fold concentration of aldehyde oxidoreductase in the latter case. However, the enzymic activity was very low in both cases. Omission of dithionite in the growth medium diminished the antigen by a factor of about 8. The immunological distance between the enzyme from C. thermoaceticum and C. thermoautotrophicum was rather low but very large to C. formicoaceticum and undeterminably large to the other organisms.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00245209
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  • 17
    Electronic Resource
    Electronic Resource
    Observations on the reduction of non-activated carboxylates by Clostridium formicoaceticum with carbon monoxide or formate and the influence of various viologens (1988)
    Springer
    Archives of microbiology 150 (1988), S. 381-386 
    Details
    ISSN: 1432-072X
    Keywords: Acylate reduction ; Clostridium formicoaceticum ; Carbon monoxide ; Formate ; Artificial mediators ; Viologens
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Crude extracts or supernatants of broken cells of Clostridium formicoaceticum reduce unbranched, branched, saturated and unsaturated carboxylates at the expense of carbon monoxide to the corresponding alcohols. The presence of viologens with redox potentials varying from E 0′=-295 to-650 mV decreased the rate of propionate reduction. The more the propionate reduction was diminished the more formate was formed from carbon monoxide. The lowest propionate reduction and highest formate formation was observed with methylviologen. The carbon-carbon double bond of E-2-methyl-butenoate was only hydrogenated when a viologen was present. Formate as electron donor led only in the presence of viologens to the formation of propanol from propionate. The reduction of propionate at the expense of a reduced viologen can be followed in cuvettes. With respect to propionate Michaelis Menten behavior was observed. Experiments are described which lead to the assumption that the carboxylates are reduced in a non-activated form. That would be new type of biological reduction.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00408311
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  • 18
    Electronic Resource
    Electronic Resource
    Hydrogenation with entrapped clostridium spec. LA 1 and observation on its stability (1982)
    Springer
    Biotechnology letters 4 (1982), S. 501-506 
    Details
    ISSN: 1573-6776
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Summary Clostridium spec. La 1 can be entrapped in ENT-110 with reasonable activity for the hydrogenation of Δ2-enoates or aldehydes with hydrogen gas. This catalyst can be stored for several months. In operation at 35° C it has a half-life of about 10 days. The catalyst can be reisolated and reused. The presence of an organic solvent such as decalin does not reduce its stability.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00131572
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  • 19
    Electronic Resource
    Electronic Resource
    Immobilization and stability of the NAD-dependent hydrogenase from alcaligenes eutrophus and of whole cells (1982)
    Springer
    Biotechnology letters 4 (1982), S. 489-494 
    Details
    ISSN: 1573-6776
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Summary The purified soluble NAD-dependent hydrogenase from Alcaligenes eutrophus was immobilized to porous glass beads according to the glutaraldehyde method retaining about 80% of its original activity. Entrapment of the purified hydrogenase in photo-crosslinkable prepolymers led to apparent activity yields of 10–80% dependent on the thickness of the gel film. The storage stability of entrapped hydrogenase (t/2 = 4 d) was considerably lower than that of glass-bound hydrogenase (t/2 = 150 d). During continuous production of NADH (turnover conditions), the half-life of entrapped hydrogenase was not longer than 10 h. Whole cells of A. eutrophus entrapped in a polyurethane matrix were used to produce NADH with hydrogen gas as electron donor. After 18 runs for 4h each and storage periods overnight the residual activity was still about 50%.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00131570
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  • 20
    Electronic Resource
    Electronic Resource
    1-Desoxy-1-[methyl-aryl-amino]-D-fructosen durch Amadori-UmlagerungListe der im Text aufgeführten Verbindungen: Ia1-Desoxy-1-p-toluidino-D-fructose (= p-Tolyl-D-isoglucosamin)Ib1-Desoxy-1-p-toluidino-4.6-benzal-D-fructoseII1-Desoxy-1-piperidino-D-fructoseIIIa1-Desoxy-1-[N-methyl-p-toluidino]-D-fructoseIIIb1-Desoxy-1-[N-methyl-p-toluidino]-4.6-benzal-D-fructoseIVa1-Desoxy-1-[N-methyl-anilino]-D-fructoseIVb1-Desoxy-1-[N-methyl-anilino]-4.6-benzal-D-fructoseVa1-Desoxy-1-anilino-D-fructoseVb1-Desoxy-1-anilino-4.6-benzal-D-fructose (1959)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 92 (1959), S. 3117-3121 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Es wird die Darstellung einiger 1-Desoxy-1-[methyl-aryl-amino]-D-fructosen beschrieben. Ihre Eigenschaften wurden mit denen der bekannten 1-Desoxy-1-aryl-amino-D-fructosen verglichen. Bemerkenswert ist, daß die N-Methyl-aryl-Verbindungen in festem Zustand eine freie CO-Gruppe besitzen.  -  Ferner gelang die Darstellung von kristallisierter 1-Desoxy-1-anilino-D-fructose.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19590921215
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