Journal of Molecular Catalysis B Enzymatic (J MOL CATAL B-ENZYM )

Publisher: Elsevier

Description

The journal is an international forum devoted to research and developments in the applications of whole-cell and cell-free enzymes as catalysts in organic synthesis. Emphasis is focused on mechanistic and synthetic aspects of the biocatalytic transformation.Papers deal with the following topics; Industrial applications of enzymatic processes, e.g. in fine chemical synthesis; Chemo-, regio- and enantioselective transformations; Screening for biocatalysts; Integration of biocatalytic and chemical steps in organic syntheses; Novel biocatalysts, e.g. enzymes from extremophiles and catalytic antibodies; Enzyme immobilization and stabilization, particularly in non-conventional media; Bioprocess engineering aspects, e.g. membrane bioreactors; Improvement of catalytic performance of enzymes, e.g. by protein engineering or chemical modification; Structural studies, including computer simulation, relating to substrate specificity and reaction selectivity; Biomimetic studies related to enzymatic transformations.

Impact factor 2.75

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    Impact factor
  • 5-year impact
    2.81
  • Cited half-life
    5.60
  • Immediacy index
    0.54
  • Eigenfactor
    0.01
  • Article influence
    0.60
  • Website
    Journal of Molecular Catalysis B: Enzymatic website
  • Other titles
    Journal of molecular catalysis
  • ISSN
    1873-3158
  • OCLC
    39177340
  • Material type
    Document, Periodical, Internet resource
  • Document type
    Internet Resource, Computer File, Journal / Magazine / Newspaper

Publisher details

Elsevier

  • Pre-print
    • Author can archive a pre-print version
  • Post-print
    • Author can archive a post-print version
  • Conditions
    • Pre-print allowed on any website or open access repository
    • Voluntary deposit by author of authors post-print allowed on authors' personal website, arXiv.org or institutions open scholarly website including Institutional Repository, without embargo, where there is not a policy or mandate
    • Deposit due to Funding Body, Institutional and Governmental policy or mandate only allowed where separate agreement between repository and the publisher exists.
    • Permitted deposit due to Funding Body, Institutional and Governmental policy or mandate, may be required to comply with embargo periods of 12 months to 48 months .
    • Set statement to accompany deposit
    • Published source must be acknowledged
    • Must link to journal home page or articles' DOI
    • Publisher's version/PDF cannot be used
    • Articles in some journals can be made Open Access on payment of additional charge
    • NIH Authors articles will be submitted to PubMed Central after 12 months
    • Publisher last contacted on 18/10/2013
  • Classification
    ​ green

Publications in this journal

  • Meng Zhang, Qian Zhao, Yan-Yan Liang, Jiang-Hao Ma, Li-Xia Chen, Xue Zhang, Li-Qin Ding, Feng Zhao, Feng Qiu
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    ABSTRACT: Biotransformations of curcumenol (1) were performed by four fungal strains, Mucor spinosus AS 3.2450, Penicillium urticae IFFI 04015, Cunninghamella echinulata AS 3.3400, Aspergillus carbonarius IFFI 02087. Five metabolites were prepared in the biotransformation process of 1, and their structures were elucidated as 15-hydroxycurcumenol (2), 1α-hydroxycurcumenol (3), 14-hydroxycurcumenol (4), 3β-hydroxycurcumenol (5) and 12-hydroxycurcumenol (6) by spectroscopic data analysis. Among them, metabolites 2-5 are novel. All of these four fungal strains showed the ability of highly stereo- and regiospecific hydroxylation for the substrate (1), which could be used as tools for preparing the hydroxylated derivatives and in vivo metabolites of curcumenol. In addition, the inhibitory effects of substrate and obtained products on nitric oxide production in lipopolysaccaride-activated macrophages were evaluated. The substrate (1) and metabolites 2, 5, and 6 showed significant inhibitory effects.
    Journal of Molecular Catalysis B Enzymatic 01/2015;
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    ABSTRACT: This study describes optimization of polygalacturonase (PG) production using Bacillus subtilis in submerged fermentation by Plackett-Burman (PB) design and response surface methodology (RSM). Five variables (pH, time, temperature, yeast extract concentration and K2HPO4), which were determined to be significant by the PB analysis, were further optimized using Box-Behnken response surface method. The optimization results indicated that a maximal PG activity of 5.60 U mL−1 was achieved at pH 7.0, 72 h, and 30 °C using 0.5% (w/v) yeast extract and 0.02% (w/v) K2HPO4 in the fermentation medium. The results implied a 2.7 fold increase in PG activity of B. subtilis under the optimized conditions. Thus, it was concluded that hazelnut shell hydrolyzate have remarkable potential for low cost commercial PG production.
    Journal of Molecular Catalysis B Enzymatic 01/2015;
  • Abid Ali Khaskhel, Farah N. Talpur, Muhammad Aqeel Ashraf, Aysun Cebeci, Sana Jawaid, Hassan Imran Afridi
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    ABSTRACT: A rapid and environmental friendly Attenuated total reflectance Fourier-transform infrared (ATR-FTIR) spectroscopic method was developed for monitoring the Rhizopus oryzae lipase (ROL) catalyzed hydrolysis of castor oil in oil-in-water emulsion system. A calibration curve was constructed using partial least square (PLS) model by gravimetric addition of oleic acid (10-50%) in castor oil to detect the carbonyl absorption of free fatty acids (FFA) in the region (1690-1730 cm−1). The correlation co-efficient (R2) and root mean square error of calibration (RMSEC) by PLS model were found to be 0.999 and 0.316 respectively. ROL was found to be an efficient biocatalyst to produce free fatty acids (FFA) from castor oil. Factors affecting the rate of hydrolysis such as enzyme concentration (0.01% w/v), pH (7), temperature (37 0C), oil-water ratio (1:4) and reaction time (12 h) were optimized. Under all set of conditions the ROL effectively hydrolyzed castor oil up to 90% yield of fatty acids. The methodology is fairly environmental friendly in both cases i-e using lipase for hydrolysis of castor oil and analyzing the product through FTIR spectroscopy.
    Journal of Molecular Catalysis B Enzymatic 01/2015;
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    ABSTRACT: Arthrobacter globiformis C224 is an industrial 2-keto-gluconic acid (2KGA) producer and currently used for erythorbic acid production in China. In the present study, a membrane-bound gluconate dehydrogenase (GADH) with specific activity of 326.06 U/mg and purification fold of 412 was purified from A. globiformis using a five-step procedure including ultrasonication, phase separation with Triton X-114, ammonium sulfate fractionation, DEAE-Sepharose fast flow and Hydroxyapatite column chromatography. The GADH was identified as to be flavin adenine dinucleotide (FAD)-dependent and consisted of three subunits with molecular mass of 66000 Da, 44000 Da and 23000 Da. The optimal pH and temperature of A. globiformis GADH were 5.0 and 40 °C, respectively. It had the stable activity at pH of 5.0-7.0 or below 50 °C, and the strict substrate specificity for D-gluconate with the Km of 3.15 mmol/L, 1.04 mmol/L at pH 5.0 and pH 6.0, respectively. The GADH activity also was significantly influenced by metal ions, organic solvents, and organic acids. Our study will benefit for better understanding of 2KGA production process by A. globiformis C224.
    Journal of Molecular Catalysis B Enzymatic 01/2015;
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    ABSTRACT: Chiral vicinal amino alcohols are molecules with broad applications in the pharmaceutical as well as in the chemical industry. Due to their high potential, various multi-step chemical, chemo-enzymatic and enzymatic reaction synthesis strategies have been developed within the last decades. This review summarises the asymmetric synthetic routes towards vicinal amino alcohols in general and provides exemplary in-depth looks into multi-step phenylpropanolamine synthesis with special focus on recently published cascade approaches.
    Journal of Molecular Catalysis B Enzymatic 01/2015;
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    ABSTRACT: The aspartate aminotransferase (AAT) and aspartate ammonia-lyase (AAL) catalyzes respectively the reversible reaction of oxaloacetate (OAA) and fumarate to form L-aspartate. However, the effects of AAT and AAL on metabolite variations have not been clearly elucidated as yet. Now, the effects of AAT and AAL on metabolite variations in genetically defined L-lysine producing strains were studied by genetically modifying AAT gene aspB and AAL gene aspA. AAL was not detected in C. glutamicum Lys1 but increased in aspB-deleted strain. Inversely, AAT exhibited high activity in Lys1, but it was not detected in aspB-deleted strains. Moreover, the deletion of aspB was bad for cell growth and metabolites production. The expression of Escherichia coli aspA in aspB-deleted strain not only restored cell growth and L-lysine production, but also accumulated some metabolites. However, the over-expression of aspB or aspA in aspB-natural strain did not affect cell growth and metabolites production except L-aspartate production. Although E. coli AAL could used to restore cell growth and metabolites accumulation in aspB-deleted strain, the effect on L-lysine production was significantly worse than that of AAT. Results indicates that native AAT is both necessary and sufficient for cell growth and L-lysine production, and deepens our understanding of the role of native aspB and E. coli aspA on cell growth and metabolites productions.
    Journal of Molecular Catalysis B Enzymatic 01/2015;
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    ABSTRACT: ZnO nanowires/macroporous SiO2 composites were used as a new type of microwave absorbing support to immobilize Candida rugosa lipase (CRL). Under microwave irradiation the immobilized lipase was used to catalyze esterification of phytosterol and oleic acid for the synthesis of phytosterol esters. A great improvement of the catalytic activity was found in the systems in which composited ZnO nanowires were present. The microwave absorbing properties of ZnO nanowires has been proved to be helpful for the synergistic effect between microwave irradiation and enzyme catalysis. The immobilized CRL showed higher thermal stability at 55 °C under microwave irradiation than conventional heating. A maximum molar conversion of 95.4% under microwave irradiation was achieved under the optimal condition: 0.1 M phytosterol, 0.2 M oleic acid, water activity (aw) of 0.11, reaction temperature at 50 °C and reaction time of 1 h.
    Journal of Molecular Catalysis B Enzymatic 01/2015;
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    ABSTRACT: In this work, the epoxidation of monoterpenes in the presence of Candida antartica lipase B (CALB) by the in-situ generation of a peroxy acid was combined with the industrial anthraquinone (AQ) process of hydrogen peroxide production. The reaction cascade consists of two major steps: reduction of an AQ to its corresponding anthrahydroquinone (AHQ) followed by the reverse auto-oxidation step of AHQ to AQ yielding equimolar amounts of hydrogen peroxide. Temperatures for each of the steps, ratio of substrate to catalyst, possible inhibition of lipases by the AQ and reaction medium (a mixture of hydrophobic and hydrophilic solvents) to be used were investigated. By using this reaction cascade, the addition of large amounts of hydrogen peroxide was avoided and conversions to epoxides of up to 83 (± 9) % for limonene, 76 (± 8)% for α-pinene and 82 (± 8)% for 3-carene were achieved within 16 h.
    Journal of Molecular Catalysis B Enzymatic 01/2015;
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    ABSTRACT: The astonishing efficiency with which living organisms build complex molecules from simple starting materials has inspired chemists for centuries. Among the synthetic strategies that nature uses to achieve this efficiency, the combination of several enzymatic transformations in cascading sequences is of outstanding importance. With the rise of biocatalysis, researchers now have the tools at hand to mimic this strategy and develop artificial enzyme cascades of impressive complexity. This editorial review aims to introduce the reader to some key aspects of (Chemo)enzymatic Cascades, as well as to put the submissions to the present Special Issue into a broader context.
    Journal of Molecular Catalysis B Enzymatic 01/2015;
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    ABSTRACT: The function of proteins, such as the catalytic enzyme activity, depends on the interaction of their active sites with their specific substrates and the environment conditions that affect the stability of those sites. This study presents a structure-to-function characterization of the folding process of a recombinant 6x–His tag leucine aminopeptidase (rLAP) based on a platform of analytical techniques. The results demonstrated an increase up to 31 U/mg in the activity of the enzyme after folding as revealed by circular dichroism, intrinsic fluorescence, differential scanning calorimetry, and free thiol analysis. Collectively, these techniques revealed a larger number of covalent and non-covalent bonds within the protein seen as an increase in the chemical and thermal stability, while exhibited a lower level of non-bonded cysteines after the protein was folded. Mass spectrometry analysis showed the maintenance of the distribution of the enzyme isoforms related to N-terminal histidine residues after folding, which confirmed that the enzymatic activity of rLAP depends on its three-dimensional structure rather than N-terminal self-processing activity. In summary, the studied attributes allow a better understanding of the structure-to-function relationship of rLAP, that permit a more proficient manufacturing of the enzyme that would improve the bioprocesses in which is employed.
    Journal of Molecular Catalysis B Enzymatic 01/2015;
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    ABSTRACT: The GH3 β-glucosidase gene from Thermotoga thermarum DSM 5069T was cloned and overexpressed in Escherichia coli. The activity of recombinant β-glucosidase was 26 U/mL in LB medium after IPTG induction. The recombinant β-glucosidase was purified by heat treatment followed by Ni-NTA affinity, and the protein's molecular weight was approximately 82 kDa. The optimal activity was at pH 5.0 and 90 °C. The enzyme was stable over the pH range of 4.5 to 7.5 and had a 1-h half-life at 90 °C. The Kcat and Km for p-nitrophenyl-β-D-glucopyranoside were 121 s−1 and 0.065 mM, respectively. The β-glucosidase exhibited high selectivity to cleave the outer and inner glucopyranosyl moieties at the C-20 carbon of ginsenoside Rb1 and catalyzed the conversion of ginsenoside Rb1 or Rd to the more pharmacologically active minor ginsenoside 20(S)-Rg3. At a concentration of 0.75 U/mL of the enzyme, a temperature of 85 °C and pH 5.0, 10 g/L ginsenoside Rb1 was transformed into 6.9 g/L Rg3 within 60 min with a corresponding molar conversion of 97.8%. BGL3 T hydrolyzed ginsenoside Rb1 along the following pathway: Rb1→Rd→Rg3. This manuscript provides the first report of the production of ginsenoside 20(S)-Rg3 by a highly thermostable β-glucosidase.
    Journal of Molecular Catalysis B Enzymatic 01/2015;
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    ABSTRACT: A multistep stereoselective synthesis of each stereoisomer of Nicotiana tabacum lactone is reported. A two steps reduction of an α,β-unsaturated ketoester gives the corresponding key intermediate ethyl 4-hydroxy-3-methylpentanoate. This one pot synthesis was catalyzed by a multienzymatic system comprising an ene-reductase (ER) and an alcohol dehydrogenase (ADH). This cascade process was highly chemoselective and stereoselective. In the last step, treatment of the hydroxyester with trifluoroacetic acid gives the γ-lactone in a very high overall yield (up to 78%) and with an excellent stereoselectivity (de >94%, ee >98%). The access to each stereoisomer was achieved by a substrate engineering approach and by selecting a Prelog or an anti-Prelog ADH. Furthermore, computational studies of the binding modes of the substrates into the catalytic site of ene-reductases have been carried out, giving an insight of the observed enantiodivergence.
    Journal of Molecular Catalysis B Enzymatic 12/2014;
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    ABSTRACT: Metalloproteases represent the largest fraction of the global enzyme market. For biotechnological purposes the accumulation of product (i.e. productivity) provides the best measure of assessing enzyme performance because it takes into account the interplay between activity, stability, activation and inhibition. Studies assessing the productivity of alkaline metalloproteases and chemicals that improve their productivity have not previously been reported. In this study we report the specificity, productivity, kinetic and thermodynamic properties of an extracellular protease, purified from a new strain of Pseudomonas sp. isolated from refrigerated milk. Mass spectrometry analysis revealed the enzyme is a serralysin-type alkaline metalloprotease, with broad cleavage-site specificity. By studying the effects of Ca2+ ion removal (using a chelator) and Ca2+ ion addition, conditions were identified that led to an increase in productivity by 300% (6.3 vs 1.9 mg azopeptide μg−1 enzyme at 40 °C). The basis for the enhanced productivity was linked to elevated melting temperatures of secondary (Tm 47 vs 38 °C) and tertiary structure (Tm 50 vs 44 °C), increased half-life of inactivation (t1/2 30 vs 4.9 min), increased optimum temperature (44 vs 36 °C), and changes in both catalytic activity (kcat 3.3 vs 2.2 min−1) and substrate affinity (Km 3.9 vs 2.5 mg ml−1). Thermodynamic data were indicative of Ca2+-binding causing the transition-state to be more ordered (less entropy) relative to the folded-state, thereby resisting a transition to an unfolded state. The specificity, kinetics and response to calcium of this AMP illustrate its potential usefulness for industrial applications, and the research highlights the broader potential for using calcium to enhance the productivity of proteases.
    Journal of Molecular Catalysis B Enzymatic 12/2014;
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    ABSTRACT: A cytosolic medium-chain alcohol dehydrogenase Gox0313 from Gluconobacter oxydans DSM2003 was heterologously expressed in E. coli BL21 (DE3) and the resulting proteins were purified and characterized. The recombinant enzyme was confirmed to have a good ability to selectively oxidize the terminal hydroxyl group of varied aliphatic and aromatic diols to the corresponding hydroxyl aldehydes, with no oxidative activities toward hydroxyl aldehydes in the presence of NAD+. This enzyme could not oxidize sec-alcohols. Among the primary diols, ethylene glycol was efficiently converted to glycolaldehyde by Gox0313 coupled with NADH oxidase-2 (NOX-2) from Lactobacillus brevis ATCC367 for NAD+ regeneration. Under the optimal conditions using this enzyme-coupled system (1 U/mL Gox0313 and 4 U/mL NOX-2), 42.32 mM glycolaldehyde was produced from 50 mM ethylene glycol in 8 h with a yield of 83.2%. When the enzyme concentration of Gox0313 was increased to 120 U/mL in the reaction, 500 mM of ethylene glycol was converted to 484.2 mM of glycolaldehyde in 14 h, resulting in a yield of 96.8%. With respect to the superior catalytic activity to primary diols, Gox0313 might be a potentially promising biocatalyst for bioproduction of glycolaldehyde and other hydroxyl aldehydes.
    Journal of Molecular Catalysis B Enzymatic 12/2014;
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    ABSTRACT: Since the preparation of nucleoside 5′-diphosphates by classical methodologies is complex, multistep enzymatic systems were explored to synthesize pyrimidine nucleoside 5′-diphosphates starting from readily available reagents. Different strategies were combined to prepare uridine- and thymidine 5′-diphosphates as ribo- and deoxyribonucleoside models, respectively. For uridine 5′-diphosphate synthesis, conversions between 38 and 66% were achieved, using a simple methodology that involves commercial yeast extract as biocatalyst and biocatalytically in situ prepared uridine 5′-monophosphate. Corynebacterium ammoniagenes ATCC 19350 was used for the first time as biocatalyst to synthesize uridine 5′-monophosphate from uracil and orotic acid while Raoultella planticola was the selected biocatalyst for uridine 5′-monophosphate synthesis from uridine. The overall performances of all the tested approaches were similar but the use of uracil leads to a more suitable and cheaper process. Alternatively, for thymidine 5′-diphosphate synthesis two consecutive one pot multistep enzyme systems were assayed. In the first biotransformation, 2′-deoxyribose 5-phosphate was formed from glucose by Erwinia carotovora whole cells followed by the action of phosphopentomutase and thymidine phosphorylase affording thymidine in 85% conversion relative to 2′-deoxyribose 5-phosphate. Finally, in the second one pot reaction, the nucleoside was converted to thymidine 5′-diphosphate by the combined action of E. coli BL21 pET22b-phoRp and Saccharomyces cerevisiae.
    Journal of Molecular Catalysis B Enzymatic 12/2014;
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    ABSTRACT: An easy and convenient chemo-enzymatic method for preparation of 1-deoxygalactonojirimycin and 1- deoxynojirimycin hydrochlorides has been demonstrated. All the compounds prepared have been characterized by MASS, 1H NMR, 13C NMR and SOR.
    Journal of Molecular Catalysis B Enzymatic 12/2014;
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    ABSTRACT: The computationally designed βD484 N mutant of penicillin acylase from Escherichia coli was shown to be more stable at alkaline conditions, resistant to inactivation by high substrate concentrations and able to catalyze preparative peptide synthesis in aqueous medium more effectively. The ability of the βD484 N mutant to operate in alkaline aqueous medium allowed to reach up to 80% yields of D-phenylglycine-derived peptide synthesis from equimolar substrate mixtures while with the wild type penicillin acylase conversion was below 17%.
    Journal of Molecular Catalysis B Enzymatic 12/2014;
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    ABSTRACT: This paper reports the identification, heterologous expression in E. coli and characterization of TtMCO from the thermophilic bacterium Thermobaculum terrenum, the first Laccase-like Multi-Copper Oxidase (LMCO) from the distinct Phylum Chloroflexi. TtMCO has only 39% identity to its closest characterized homolog, CotA from Bacillus subtilis, but sequence and spectrophotometry confirmed copper coordination similar to that of LMCOs. TtMCO is extremely thermophilic with a half-time of inactivation of 2.24 days at 70 °C and 350 minutes at 80 °C and pH 7, consistent with a hyperthermal habitat of the host. TtMCO was screened for activity against 56 chemically diverse substrates: It displayed limited activity on classical LMCO substrates, such as e.g. phenolics, transition metals, or bilirubin. Highest activities were observed for nitrogen-containing aromatic compounds, i.e. 1,8-diaminonaphtalene (Km = 0.159 mM, kcat = 0.295 s−1) and ABTS (Km = 0.844 mM, kcat = 2.13 s−1). The combined data suggest a distinct role of TtMCO and a substantial trade-off between activity and stability, compared to other characterized bacterial LMCOs, making it of interest in future protein engineering studies.
    Journal of Molecular Catalysis B Enzymatic 12/2014;
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    ABSTRACT: The homodimeric Candida parapsilosis carbonyl reductase 2 (CPCR2) is an industrially attractive biocatalyst due to its broad substrate range and high stereoselectivity. In addition, CPCR2 is reasonably stable in monophasic organic solvents (e.g. alcohols) but apparently instable in biphasic organic systems. Hence, we conducted first a thorough quantitative inactivation study of CPCR2, using both wild-type and stability improved variants, in an attempt to identify critical factors influencing the enzyme stability. Possible inactivation phenomena including oxidation, shear forces, dissociation and adsorption at interfaces were assessed on a microliter scale using quantitative kinetic assays. Our results demonstrate that interface interactions and dimer dissociation are the main reasons for inactivation of CPCR2. Shear forces seems to enhance these inactivation processes whereas oxidation plays no role in CPCR2 inactivation. Secondly, an attempt was made to find suitable stabilization strategies to utilize CPCR2 in various reaction systems. To minimize the inactivation, bovine serum albumin was used as traditional blocking and crowding agent. The residual activity of the wild-type was successfully increased up to 2.5-fold by addition of 1 μg mL−1 bovine serum albumin. To avoid dimer dissociation the cofactor concentration was successively increased. The residual activity was successfully enhanced up to 5-fold, 3-fold and 1.5-fold for the wild-type, single and double mutant, respectively. Further, recently gained data from the enzyme crystal structure were used to interpret the effects of stabilization. We propose conformational change of a flexible region in CPCR2 upon binding of the cofactor leading to internal stabilization of the enzyme. In conclusion, we propose the addition of bovine serum albumin and the cofactor NADH as a suitable stabilization strategy to utilize CPCR2 in various reaction systems.
    Journal of Molecular Catalysis B Enzymatic 12/2014;