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1.
Su Keun Kuk Youngjin Ham Krishnasamy Gopinath Passarut Boonmongkolras Youngjun Lee Yang Woo Lee Sanath Kondaveeti Changui Ahn Byungha Shin Jung‐Kul Lee Seokwoo Jeon Chan Beum Park 《Liver Transplantation》2019,9(25)
Z‐scheme‐inspired tandem photoelectrochemical (PEC) cells have received attention as a sustainable platform for solar‐driven CO2 reduction. Here, continuously 3D‐structured, electrically conductive titanium nitride nanoshells (3D TiN) for biocatalytic CO2‐to‐formate conversion in a bias‐free tandem PEC system are reported. The 3D TiN exhibits a periodically porous network with high porosity (92.1%) and conductivity (6.72 × 104 S m?1), which allows for high enzyme loading and direct electron transfer (DET) to the immobilized enzyme. It is found that the W‐containing formate dehydrogenase from Clostridium ljungdahlii (ClFDH) on the 3D TiN nanoshell is electrically activated through DET for CO2 reduction. At a low overpotential of 40 mV, the 3D TiN‐ClFDH stably converts CO2 to formate at a rate of 0.34 µmol h?1 cm?2 and a faradaic efficiency (FE) of 93.5%. Compared to a flat TiN‐ClFDH, the 3D TiN‐ClFDH shows a 58 times higher formate production rate (1.74 µmol h?1 cm?2) at 240 mV of overpotential. Lastly, a bias‐free biocatalytic tandem PEC cell that converted CO2 to formate at an average rate of 0.78 µmol h?1 and an FE of 77.3% only using solar energy and water is successfully assembled. 相似文献
2.
Guan Wang Xinxin Wang Tong Wang Walter van Gulik Henk J. Noorman Yingping Zhuang Ju Chu Siliang Zhang 《Biotechnology journal》2019,14(10)
During glucose‐limited growth, a substantial input of adenosine triphosphate (ATP) is required for the production of β‐lactams by the filamentous fungus Penicillium chrysogenum. Formate dehydrogenase has been confirmed in P. chrysogenum for formate oxidation allowing an extra supply of ATP, and coassimilation of glucose and formate has the potential to increase penicillin production and biomass yield. In this study, the steady‐state metabolite levels and fluxes in response to cofeeding of formate as an auxiliary substrate in glucose‐limited chemostat cultures at the dilution rates (D) of both 0.03 h?1 and 0.05 h?1 are determined to evaluate the quantitative impact on the physiology of a high‐yielding P. chrysogenum strain. It is observed that an equimolar addition of formate is conducive to an increase in both biomass yield and penicillin production at D = 0.03 h?1, while this is not the case at D = 0.05 h?1. In addition, a higher cytosolic redox status (NADH/NAD+), a higher intracellular glucose level, and lower penicillin productivity are only observed upon formate addition at D = 0.05 h?1, which are virtually absent at D = 0.03 h?1. In conclusion, the results demonstrate that the effect of formate as an auxiliary substrate on penicillin productivity in the glucose‐limited chemostat cultivations of P. chrysogenum is not only dependent on the formate/glucose ratio as published before but also on the specific growth rate. The results also imply that the overall process productivity and quality regarding the use of formate should be further explored in an actual industrial‐scale scenario. 相似文献
3.
Aims: To characterize a robust NAD+‐dependent formate dehydrogenase firstly obtained from a nonmethylotroph, Bacillus sp. F1. Methods and Results: The Bacillus sp. F1 NAD+‐dependent formate dehydrogenase (BacFDH) gene was cloned by TAIL‐PCR and heterologous expressed in Escherichia coli. BacFDH was stable at temperatures below 55°C, and the half‐life at 60°C was determined as 52·9 min. This enzyme also showed a broad pH stability and retained more than 80% of the activities after incubating in buffers with different pH ranging from 4·5 to 10·5 for 1 h. The activity of BacFDH was significantly enhanced by some metal ions. Moreover, BacFDH exhibited high tolerance to 20% dimethyl sulfoxide, 60% acetone, 10% methanol, 20% ethanol, 60% isopropanol and 20% n‐hexane. Like other FDHs, BacFDH displayed strict substrate specificity for formate. Conclusion: We isolated a robust formate dehydrogenase, designated as BacFDH, which showed excellent thermal stability, organic solvent stability and a broad pH stability. Significance and Impact of the Study: The multi‐aspect stability makes BacFDH a competitive candidate for coenzyme regeneration in practical applications of chiral chemicals and pharmaceuticals synthesis with a relatively low cost, especially for the catalysis performed in extreme pH conditions and organic solvents. 相似文献
4.
Shuhuai Yu Lanjun Zhu Chen Zhou Tao An Tao Zhang Bo Jiang Wanmeng Mu 《Applied microbiology and biotechnology》2014,98(4):1621-1630
The cDNA gene coding for formate dehydrogenase (FDH) from Ogataea parapolymorpha DL-1 was cloned and expressed in Escherichia coli. The recombinant enzyme was purified by nickel affinity chromatography and was characterized as a homodimer composed of two identical subunits with approximately 40 kDa in each monomer. The enzyme showed wide pH optimum of catalytic activity from pH 6.0 to 7.0. It had relatively high optimum temperature at 65 °C and retained 93, 88, 83, and 71 % of its initial activity after 4 h of exposure at 40, 50, 55, and 60 °C, respectively, suggesting that this enzyme had promising thermal stability. In addition, the enzyme was characterized to have significant tolerance ability to organic solvents such as dimethyl sulfoxide, n-butanol, and n-hexane. The Michaelis–Menten constant (K m), turnover number (k cat), and catalytic efficiency (k cat/K m) values of the enzyme for the substrate sodium formate were estimated to be 0.82 mM, 2.32 s?1, and 2.83 mM?1 s?1, respectively. The K m for NAD+ was 83 μM. Due to its wide pH optimum, promising thermostability, and high organic solvent tolerance, O. parapolymorpha FDH may be a good NADH regeneration catalyst candidate. 相似文献
5.
J. P. Van Dijken G. J. Oostra-Demkes R. Otto W. Harder 《Archives of microbiology》1976,111(1-2):77-83
Formaldehyde dehydrogenase and formate dehydrogenase were purified 45- and 16-fold, respectively, from Hansenula polymorpha grown on methanol. Formaldehyde dehydrogenase was strictly dependent on NAD and glutathione for activity. The K
mvalues of the enzyme were found to be 0.18 mM for glutathione, 0.21 mM for formaldehyde and 0.15 mM for NAD. The enzyme catalyzed the glutathine-dependent oxidation of formaldehyde to S-formylglutathione. The reaction was shown to be reversible: at pH 8.0 a K
mof 1 mM for S-formylglutathione was estimated for the reduction of the thiol ester with NADH. The enzyme did not catalyze the reduction of formate with NADH. The NAD-dependent formate dehydrogenase of H. polymorpha showed a low affinity for formate (K
mof 40 mM) but a relatively high affinity for S-formylglutathione (K
mof 1.1 mM). The K
mvalues of formate dehydrogenase in cell-free extracts of methanol-grown Candida boidinii and Pichia pinus for S-formylglutathione were also an order of magnitude lower than those for formate. It is concluded that S-formylglutathione rather than free formate is an intermediate in the oxidation of methanol by yeasts. 相似文献
6.
3,4‐Dihydroxy‐2‐butanone‐4‐phosphate synthase (DHBPS) encoded by ribB gene is one of the first enzymes in riboflavin biosynthesis pathway and catalyzes the conversion of ribulose‐5‐phosphate (Ru5P) to 3,4‐dihydroxy‐2‐butanone‐4‐phosphate and formate. DHBPS is an attractive target for developing anti‐bacterial drugs as this enzyme is essential for pathogens, but absent in humans. The recombinant DHBPS enzyme of Salmonella requires magnesium ion for its activity and catalyzes the formation of 3,4‐dihydroxy‐2‐butanone‐4‐phosphate from Ru5P at a rate of 199 nmol min?1 mg?1 with Km value of 116 μM at 37°C. Further, we have determined the crystal structures of Salmonella DHBPS in complex with sulfate, Ru5P and sulfate‐zinc ion at a resolution of 2.80, 2.52, and 1.86 Å, respectively. Analysis of these crystal structures reveals that the acidic loop (residues 34–39) responsible for the acid‐base catalysis is disordered in the absence of substrate or metal ion at the active site. Upon binding either substrate or sulfate and metal ions, the acidic loop becomes stabilized, adopts a closed conformation and interacts with the substrate. Our structure for the first time reveals that binding of substrate Ru5P alone is sufficient for the stabilization of the acidic active site loop into a closed conformation. In addition, the Glu38 residue from the acidic active site loop undergoes a conformational change upon Ru5P binding, which helps in positioning the second metal ion that stabilizes the Ru5P and the reaction intermediates. This is the first structural report of DHBPS in complex with either substrate or metal ion from any eubacteria. Proteins 2010. © 2010 Wiley‐Liss, Inc. 相似文献
7.
NAD+-dependent formate dehydrogenase(s) (EC 1.2.1.2, FDH) catalyzes the interconversion of formate anion to carbon dioxide coupled with the conversion of NAD+ or NADH. FDHs attract significant attention in biotechnology due to their potential applications in NAD(H)-dependent industrial biocatalysis as well as in the production of renewable fuels and chemicals from carbon dioxide. In the present work, a new FDH from thermophilic fungus Myceliophthora thermophile (MtFDH) was characterized. The gene of the enzyme was synthesised, cloned, expressed in E. coli, as 6His-tagged protein, and purified to homogeneity by metal chelate affinity chromatography. Kinetic analysis suggested that MtFDH exhibits higher catalytic efficiency on NaHCO3 compared to formate. Notable, recombinant MtFDH displays a pH optimum for the conversion of formate anion to carbon dioxide at extreme alkaline pH (pH 10.5). Thermal stability analysis showed that the enzyme displays good thermostability with Tm 48 °C. Homology modelling and phylogenetic analysis suggested that the enzyme belongs to the D-specific 2-hydroxy acid dehydrogenases family. The active-site residues are well conserved compared to other homologous FDHs. The results of the present work provide new knowledge on the structure, function and diversity of FDHs and indicate that MtFDH possess a huge potential for CO2 reduction or NADH generation and under extreme alkaline conditions. 相似文献
8.
A pathway for conversion of the metabolic intermediate phosphoenolpyruvate (PEP) and the formation of acetate, succinate, formate, and H2 in the anaerobic cellulolytic bacterium Ruminococcus flavefaciens FD-1 was constructed on the basis of enzyme activities detected in extracts of cells grown in cellulose- or cellobiose-limited continuous culture. PEP was converted to acetate and CO2 (via pyruvate kinase, pyruvate dehydrogenase, and acetate kinase) or carboxylated to form succinate (via PEP carboxykinase, malate dehydrogenase, fumarase, and fumarate reductase). Lactate was not formed even during rapid growth (batch culture, µ = 0.35/h). H2 was formed by a hydrogenase rather than by cleavage of formate, and 13C-NMR and14 C-exchange reaction data indicated that formate was produced by CO2 reduction, not by a cleavage of pyruvate. The distribution of PEP into the acetate and succinate pathways was not affected by changing extracellular pH and growth rates within the normal growth range. However, increasing growth rate from 0.017/h to 0.244/h resulted in a shift toward formate production, presumably at the presence of H2. This shift suggested that reducing equivalents could be balanced through formate or H2 production without affecting the yields of the major carbon-containing fermentation endproducts. 相似文献
9.
Alcaligenes eutrophus JMP 134 was continuously (carbon-source-limited) grown on phenol to determine the maximum growth rates (μmax) as a function of the phenol assimilation pathways expressed. During growth on phenol as the sole source of carbon and energy,
an almost exclusive expression of the ortho cleavage pathway (catechol 1,2-dioxygenase) was observed at initially low growth rates. This allowed a μmax of 0.28 h-1. The induction of the meta cleavage pathway (catechol 2,3-dioxygenase), which appeared at around 0.25 h-1, resulted in a further increase in the growth rate to 0.40 h-1 after the enzyme activities of this pathway had been correspondingly expressed. Hence, two maximum growth rates, one for
the ortho and one for the meta cleavage pathway, exist for the growth of A. eutrophus JMP 134 on phenol. Growth on phenol was stimulated by formate, which served as an auxiliary energy source in this strain.
The simultaneous utilization of phenol and formate at a molar ratio of 1:5.2 resulted in an increase of the yield coefficient
from about 0.75 g dry mass/g phenol to 1.25 g/g. Furthermore, formate exerted a pronounced effect on the growth rate. At a
molar ratio of phenol to formate of 1:4.2, the growth rate was increased to 0.42 h-1, despite the exclusive induction of the ortho cleavage pathway. The meta cleavage pathway was expressed during growth on this substrate mixture at about 0.4 h-1. However, this did not enable a significant increase of the growth rate beyond 0.4 h-1. This is attributed to an exhaustion of the capacity for formate oxidation at this rate. The results are discussed with respect
to energy production capabilities when phenol is assimilated as an energy-deficient heterotrophic substrate.
Received: 13 November 1995/Received revision: 15 April 1996/Accepted: 22 April 1996 相似文献
10.
Rhizobium japonicum CJ1 was capable of growing using formate as the sole source of carbon and energy. During aerobic growth on formate a cytoplasmic NAD+-dependent formate dehydrogenase and ribulose bisphosphate carboxylase activity was demonstrated in cell-free extracts, but hydrogenase enzyme activity could not be detected. Under microaerobic growth conditions either formate or hydrogen metabolism could separately or together support ribulose bisphosphate carboxylase-dependent CO2 fixation. A number of R. japonicum strains defective in hydrogen uptake activity were shown to metabolise formate and induce ribulose bisphosphate carboxylase activity. The induction and regulation of ribulose bisphosphate carboxylase is discussed.Abbreviations hup
hydrogen uptake
- MOPS
3-(N-morpholino)-propanesulphonate
- TSA
tryptone soya agar
- RuBP
ribulose 1,5-bisphosphate
- FDH
formate dehydrogenase 相似文献
11.
Hubert G. D. Niekus Els van Doorn Adrian H. Stouthamer 《Archives of microbiology》1980,127(2):137-143
The kinetics of oxygen utilization by the microaerophile Campylobacter sputorum subspecies bubulus was studied. With formate as substrate two enzyme systems were found to be responsible for electron transfer between formate and oxygen. In the case of lactate oxidation one enzyme system could account for the activity measured. One of the formateoxidizing systems possessed a high affinity for oxygen [K
m(O2)=approx. 4M O2]. From inhibitor studies it was concluded that a respiratory chain was involved in its activity. Respiration by this system must be responsible for proton translocation and electron transport-linked phosphorylation at formate oxidation. The other enzyme system had an extremely low affinity for oxygen [K
m (O2)=approx. 1 mM O2]. It was tentatively identified as the H2O2-producing formate oxidase previously found in C. sputorum. The H2O2 production by this enzyme is implicated in an explanation of the microaerophilic nature of C. sputorum. Sensitivity of formate dehydrogenase to H2O2 was demonstrated. The influence of the formate concentration on aerobic formate oxidation was determined. The pH- and temperature dependencies of oxygen uptake with formate as substrate were examined at airsaturation and at a low dissolved oxygen tension.Abbreviations TL medium
tryptose-lactate medium
- TF medium
tryptose-formate medium
- HQNO
2-n-heptyl-4-hydroxyquinoline N-oxide
- SHAM
salicylhydroxamic acid
- DCPIP
2,6-dichlorophenolindophenol 相似文献
12.
Chistoserdova L Crowther GJ Vorholt JA Skovran E Portais JC Lidstrom ME 《Journal of bacteriology》2007,189(24):9076-9081
A mutant of Methylobacterium extorquens AM1 with lesions in genes for three formate dehydrogenase (FDH) enzymes was previously described by us (L. Chistoserdova, M. Laukel, J.-C. Portais, J. A. Vorholt, and M. E. Lidstrom, J. Bacteriol. 186:22-28, 2004). This mutant had lost its ability to grow on formate but still maintained the ability to grow on methanol. In this work, we further investigated the phenotype of this mutant. Nuclear magnetic resonance experiments with [13C]formate, as well as 14C-labeling experiments, demonstrated production of labeled CO2 in the mutant, pointing to the presence of an additional enzyme or a pathway for formate oxidation. The tungsten-sensitive phenotype of the mutant suggested the involvement of a molybdenum-dependent enzyme. Whole-genome array experiments were conducted to test for genes overexpressed in the triple-FDH mutant compared to the wild type, and a gene (fdh4A) was identified whose translated product carried similarity to an uncharacterized putative molybdopterin-binding oxidoreductase-like protein sharing relatively low similarity with known formate dehydrogenase alpha subunits. Mutation of this gene in the triple-FDH mutant background resulted in a methanol-negative phenotype. When the gene was deleted in the wild-type background, the mutant revealed diminished growth on methanol with accumulation of high levels of formate in the medium, pointing to an important role of FDH4 in methanol metabolism. The identity of FDH4 as a novel FDH was also confirmed by labeling experiments that revealed strongly reduced CO2 formation in growing cultures. Mutation of a small open reading frame (fdh4B) downstream of fdh4A resulted in mutant phenotypes similar to the phenotypes of fdh4A mutants, suggesting that fdh4B is also involved in formate oxidation. 相似文献
13.
Formate Dehydrogenase of Clostridium thermoaceticum: Incorporation of Selenium-75, and the Effects of Selenite, Molybdate, and Tungstate on the Enzyme 总被引:10,自引:6,他引:4
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The formation of the nicotinamide adenine dinucleotide phosphate-dependent formate dehydrogenase in Clostridium thermoaceticum is stimulated by the presence of molybdate and selenite in the growth medium. The highest formate dehydrogenase activity was obtained with 2.5 × 10−4 M Na2MoO4 and 5 × 10−5 Na2SeO3. Tungstate but not vanadate could replace molybdate and stimulate the formation of formate dehydrogenase. Tungstate stimulated activity more than molybdate, and in combination with molybdate the stimulation of formation of formate dehydrogenase was additive. Formate dehydrogenase was isolated from cells grown in the presence of Na275SeO2, and a correlation was observed between bound 75Se and enzyme activity. 相似文献
14.
Celeste LR Chai G Bielak M Minor W Lovelace LL Lebioda L 《Protein science : a publication of the Protein Society》2012,21(2):219-228
N10‐formyltetrahydrofolate synthetase (FTHFS) is a folate enzyme that catalyzes the formylation of tetrahydrofolate (THF) in an ATP dependent manner. Structures of FTHFS from the thermophilic homoacetogen, Moorella thermoacetica, complexed with (1) a catalytic intermediate—formylphosphate (XPO) and product—ADP; (2) with an inhibitory substrate analog–folate; (3) with XPO and an inhibitory THF analog, ZD9331, were used to analyze the enzyme mechanism. Nucleophilic attack of the formate ion on the gamma phosphate of ATP leads to the formation of XPO and the first product ADP. A channel that leads to the putative formate binding pocket allows for the binding of ATP and formate in random order. Formate binding is due to interactions with the gamma‐phosphate moiety of ATP and additionally to two hydrogen bonds from the backbone nitrogen of Ala276 and the side chain of Arg97. Upon ADP dissociation, XPO reorients and moves to the position previously occupied by the beta‐phosphate of ATP. Conformational changes that occur due to the XPO presence apparently allow for the recruitment of the third substrate, THF, with its pterin moiety positioned between Phe384 and Trp412. This position overlaps with that of the bound nucleoside, which is consistent with a catalytic mechanism hypothesis that FTHFS works via a sequential ping‐pong mechanism. More specifically, a random bi uni uni bi ping‐pong ter ter mechanism is proposed. Additionally, the native structure originally reported at a 2.5 Å resolution was redetermined at a 2.2 Å resolution. 相似文献
15.
16.
Escherichia coli (E. coli) is a versatile organism for making nucleotides labeled with stable isotopes (13C, 15N, and/or 2H) for structural and molecular dynamics characterizations. Growth of a mutant E. coli strain deficient in the pentose phosphate pathway enzyme glucose-6-phosphate dehydrogenase (K10-1516) on 2-13C-glycerol and 15N-ammonium sulfate in Studier minimal medium enables labeling at sites useful for NMR spectroscopy. However, 13C-sodium formate combined with 13C-2-glycerol in the growth media adds labels to new positions. In the absence of labeled formate, both C5 and C6 positions
of the pyrimidine rings are labeled with minimal multiplet splitting due to 1JC5C6 scalar coupling. However, the C2/C8 sites within purine rings and the C1′/C3′/C5′ positions within the ribose rings have
reduced labeling. Addition of 13C-labeled formate leads to increased labeling at the base C2/C8 and the ribose C1′/C3′/C5′ positions; these new specific labels
result in two- to three-fold increase in the number of resolved resonances. This use of formate and 15N-ammonium sulfate promises to extend further the utility of these alternate site specific labels to make labeled RNA for
downstream biophysical applications such as structural, dynamics and functional studies of interesting biologically relevant
RNAs. 相似文献
17.
Kazuo Iwai Noboru Suzuki Shusaku Mizoguchi 《Bioscience, biotechnology, and biochemistry》2013,77(3):267-274
Formyltetrahydrofolate synthetase (E. C. 6. 3. 4. 3) was found in fresh spinach leaves and purified about 60-fold by treatments of ammonium sulfate, protamine sulfate, dialysis, and DEAE-cellulose column chromatography. Some properties of the enzyme were investigated. Optimum pH was found to be 7.5, and optimum temperature was observed to be at 37°C. In the enzyme reaction, FAH4 and formate were required specifically as the substrates, and Mg++ and ATP were essential components. The Michaelis constants for dl-FAH4, formate, ATP and magnesium chloride were 1.7×10?3 m, 1.7×10?2 m, 4.1×10?4 m and 3.3×10?3 m, respectively. The primary product formed in the reaction catalyzed by the enzyme was suggested as N10-formyl-FAH4 spectrophotometrically. It was observed that the enzyme also catalyzed the reverse reaction. The possible role of the enzyme in plants was discussed. 相似文献
18.
Yaw Kai Yan Michael Melchart Abraha Habtemariam Anna F. A. Peacock Peter J. Sadler 《Journal of biological inorganic chemistry》2006,11(4):483-488
Ruthenium(II) arene anticancer complexes [(η
6-arene)Ru(en)Cl]PF6 (arene is hexamethylbenzene, p-cymene, indan; en is ethylenediamine) can catalyse regioselective reduction of NAD+ by formate in water to form 1,4-NADH, at pD 7.2, 37 °C, and in the presence of air. The catalytic activity is markedly dependent on the arene, with the hexamethylbenzene (hmb) complex showing the highest activity. For [(η
6-hmb)Ru(en)Cl]PF6, the rate of reaction is independent of NAD+ concentration and shows saturation kinetics with respect to formate concentration. A K
m value of 58 mM and a turnover frequency at saturation of 1.46 h−1 were observed. Removal of chloride and performing the reaction under argon led to higher reaction rates. Lung cancer cells (A549) were found to be remarkably tolerant to formate even at millimolar concentrations. The possibility of using ruthenium arene complexes coadministered with formate as catalytic drugs is discussed.Electronic Supplementary Material Supplementary material is available for this article at and is accessible for authorized users. 相似文献
19.
Reevaluation of the role of bicarbonate and formate in the regulation of photosynthetic electron flow in broken chloroplasts 总被引:2,自引:1,他引:1
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The stimulation of the Hill reaction in CO2-depleted broken chloroplasts (Pisum sativum L. cv Rondo) by the total amount of dissolved CO2 and HCO3− (bicarbonate*) was measured at several formate concentrations. Formate appears to be a competitive inhibitor of the bicarbonate* stimulation of electron flow. From these experiments we have obtained a reactivation constant (Kr) of 78 ± 31 micromolar NaHCO3 and an inhibition constant (Ki) of 2.0 ± 0.7 millimolar HCOONa at pH 6.5. In the absence of formate, significant electron flow was measured at a bicarbonate* concentration well below Kr, suggesting that electron flow from Q, the primary electron acceptor of photosystem II, to plastoquinone can proceed when no bicarbonate* is bound to the regulatory site at the QB-protein. If so, bicarbonate* stimulation of electron flow is mainly a diminution of the inhibition of electron flow by formate. In view of the results, it is proposed that regulation of linear electron flow by bicarbonate* and formate is a mechanism that could link cell metabolism to photosynthetic electron flow. 相似文献
20.
Extracts of Pseudomonas C grown on methanol as sole carbon and energy source contain a methanol dehydrogenase activity which can be coupled to phenazine methosulfate. This enzyme catalyzes two reactions namely the conversion of methanol to formaldehyde (phenazine methosulfate coupled) and the oxidation of formaldehyde to formate (2,6-dichloroindophenol-coupled). Activities of glutathione-dependent formaldehyde dehydrogenase (NAD+) and formate dehydrogenase (NAD+) were also detected in the extracts.The addition of d-ribulose 5-phosphate to the reaction mixtures caused a marked increase in the formaldehyde-dependent reduction of NAD+ or NADP+. In addition, the oxidation of [14C]formaldehyde to CO2, by extracts of Pseudomonas C, increased when d-ribulose 5-phosphate was present in the assay mixtures.The amount of radioactivity found in CO2, was 6.8-times higher when extracts of methanol-grown Pseudomona C were incubated for a short period of time with [1-14C]glucose 6-phosphate than with [U-14C]glucose 6-phosphate.These data, and the presence of high specific activities of hexulose phosphate synthase, phosphoglucoisomerase, glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase indicate that in methanol-grown Pseudomonas C, formaldehyde carbon is oxidized to CO2 both via a cyclic pathway which includes the enzymes mentioned and via formate as an oxidation intermediate, with the former predominant. 相似文献