A method of graphically analyzing substrate-inhibition kinetics

Wang, Jinsheng; Araki, Tetsuya; Ogawa, Takahira; Matsuoka, Masayoshi; Fukuda, Hideo

doi:10.1002/(sici)1097-0290(19990220)62:4<402::aid-bit3>3.0.co;2-v

Cited by 30 publications

(9 citation statements)

References 12 publications

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“…K M , V max , and k cat were determined by nonlinear regression of the Michaelis−Menten equation(33) using eq 1 for CS and the forward reaction of MDH, and eq 2 for the reverse reaction of MDH; this was necessary because high concentrations of oxaloacetate are known to inhibit MDH activity. 64,65 …”

Section: Methodsmentioning

confidence: 99%

Enzyme:Nanoparticle Bioconjugates with Two Sequential Enzymes: Stoichiometry and Activity of Malate Dehydrogenase and Citrate Synthase on Au Nanoparticles

Keighron¹,

Keating²

2010

Langmuir

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We report the synthesis and characterization of bioconjugates in which the enzymes malate dehydrogenase (MDH) and/or citrate synthase (CS) were adsorbed to 30 nm diameter Au nanoparticles. Enzyme:Au stoichiometry and kinetic parameters (specific activity, kcat, KM, and activity per particle) were determined for MDH:Au, CS:Au, and three types of dual-activity MDH/CS:Au bioconjugates. For single-activity bioconjugates (MDH:Au and CS:Au), the number of enzyme molecules adsorbed per particle was dependent upon the enzyme concentration in solution, with multilayers forming at high enzyme:Au solution ratios. The specific activity of adsorbed enzyme increased with increasing number adsorbed per particle for CS:Au, but was less sensitive to stoichiometry for MDH:Au. Dual activity bioconjugates were prepared in three ways: (1) by adsorption of MDH followed by CS, (2) by adsorption of CS followed by MDH, and (3) by coadsorption of both enzymes from the same solution. The resulting bioconjugates differed substantially in the number of enzyme molecules adsorbed per particle, the specific activity of the adsorbed enzymes, and also the enzymatic activity per particle. Bioconjugates formed by adding CS to the Au nanoparticles before MDH was added exhibited higher specific activities for both enzymes than those formed by adding the enzymes in the reverse order. These bioconjugates also had 3-fold higher per-particle sequential activity for conversion of malate to citrate, despite substantially fewer copies of both enzymes present.

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Section: Methodsmentioning

confidence: 99%

Enzyme:Nanoparticle Bioconjugates with Two Sequential Enzymes: Stoichiometry and Activity of Malate Dehydrogenase and Citrate Synthase on Au Nanoparticles

Keighron¹,

Keating²

2010

Langmuir

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“…The parameters K EtOH , K IEtOH , and max were estimated from an independent set of experiments, using nitrogen-flashed Erlenmeyer flasks at 10 different initial ethanol concentrations and equal biomass, acetate, and sulfate initial concentrations, where c 0Ac <<K IAc and c 0SO 4 >>K SO 4 . The linear-plot approach was then applied to the results obtained, as described by Wang et al, 1999. The linear approach is based on the equation:…”

Section: Srb Process Model For Batch Growth On Ethanolmentioning

confidence: 99%

Ethanol utilization by sulfate‐reducing bacteria: An experimental and modeling study

Nagpal¹,

Chuichulcherm²,

Livingston³

et al. 2000

Biotechnol. Bioeng.

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A mixed culture of sulfate-reducing bacteria containing the species Desulfovibrio desulfuricans was used to study sulfate-reduction stoichiometry and kinetics using ethanol as the carbon source. Growth yield was lower, and kinetics were slower, for ethanol compared to lactate. Ethanol was converted into acetate and no significant carbon dioxide production was observed. A mathematical model for growth of sulfate-reducing bacteria on ethanol was developed, and simulations of the growth experiments on ethanol were carried out using the model. The pH variation due to sulfate reduction, and hydrogen sulfide production and removal by nitrogen sparging, were examined. The modeling study is distinct from earlier models for systems using sulfate-reducing bacteria in that it considers growth on ethanol, and analyzes pH variations due to the product-formation reactions.

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“…Autotrophic production of ethylene has been studied primarily in two cyanobacterial strains S ynechocystis sp PCC 6803 (Guerrero et al 2012 ; Ungerer et al 2012 ; Eckert et al 2014 ; Zhu et al 2015 ; Lee et al 2015 ; Xiong et al 2015 ; Zavřel et al 2016 ; Carbonell et al 2016 ) and Synechococcus elongatus PCC 7942 (Fukuda et al 1994 ; Sakai et al 1997 ; Wang et al 1999 , 2000 ; Matsuoka et al 2001 ; Takahama et al 2003 ) (from here on referred to as Synechocystis and Synechococcus , respectively). The general strategy has been to over-express the heterologous ethylene forming enzyme from Pseudomonas syringae to convert endogenous metabolic precursors 2-oxoglutarate and l -arginine to ethylene, which then as a volatile gas spontaneously diffuses out from the cell and separates into the culture headspace.…”

Section: Introductionmentioning

confidence: 99%

Enhanced stable production of ethylene in photosynthetic cyanobacterium Synechococcus elongatus PCC 7942

Carbonell

Vuorio

Aro

et al. 2019

World J Microbiol Biotechnol

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Ethylene is a volatile alkene which is used in large commercial scale as a precursor in plastic industry, and is currently derived from petroleum refinement. As an alternative production strategy, photoautotrophic cyanobacteria Synechocystis sp. PCC 6803 and Synechococcus elongatus PCC 7942 have been previously evaluated as potential biotechnological hosts for producing ethylene directly from CO 2 , by the over-expression of ethylene forming enzyme (efe) from Pseudomonas syringae . This work addresses various open questions related to the use of Synechococcus as the engineering target, and demonstrates long-term ethylene production at rates reaching 140 µL L −1 h −1 OD 750 −1 without loss of host vitality or capacity to produce ethylene. The results imply that the genetic instability observed earlier may be associated with the expression strategies, rather than efe over-expression, ethylene toxicity or the depletion of 2-oxoglutarate—derived cellular precursors in Synechococcus . In context with literature, this study underlines the critical differences in expression system design in the alternative hosts, and confirms Synechococcus as a suitable parallel host for further engineering. Electronic supplementary material The online version of this article (10.1007/s11274-019-2652-7) contains supplementary material, which is available to authorized users.

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A method of graphically analyzing substrate-inhibition kinetics

Cited by 30 publications

References 12 publications

Enzyme:Nanoparticle Bioconjugates with Two Sequential Enzymes: Stoichiometry and Activity of Malate Dehydrogenase and Citrate Synthase on Au Nanoparticles

Enzyme:Nanoparticle Bioconjugates with Two Sequential Enzymes: Stoichiometry and Activity of Malate Dehydrogenase and Citrate Synthase on Au Nanoparticles

Ethanol utilization by sulfate‐reducing bacteria: An experimental and modeling study

Enhanced stable production of ethylene in photosynthetic cyanobacterium Synechococcus elongatus PCC 7942

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