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Su A, Kiokekli S, Naviwala M, Shirke AN, Pavlidis IV, Gross RA. Cutinases as stereoselective catalysts: Specific activity and enantioselectivity of cutinases and lipases for menthol and its analogs. Enzyme Microb Technol 2020; 133:109467. [PMID: 31874689 DOI: 10.1016/j.enzmictec.2019.109467] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 11/08/2019] [Accepted: 11/11/2019] [Indexed: 12/15/2022]
Abstract
The specific activity and enantioselectivity of immobilized cutinases from Aspergillus oryzae (AoC) and Humicola insolens (HiC) were compared with those of lipases from Thermomyces lanuginosus (TLL), Rhizomucor miehei (RML) and Lipase B from Candida antarctica (CALB) for menthol and its analogs that include isopulegol, trans-2-tert-butylcyclohexanol (2TBC), and dihydrocarveol (DHC). Common features of these alcohols are two bulky substituents: a cyclohexyl ring and an alkyl substituent. Dissimilarities are that the alkyl group reside at different positions or have dissimilar structures. The aim was to develop an understanding at a molecular level of similarities and differences in the catalytic behavior of the selected cutinases and lipases as a function of substrate structural elements. The experimental results reflect the (-)-enantioselectivity for AoC, HiC, TLL, and RML, while CALB is only active on DHC with (+)-enantioselectivity. In most cases, AoC has the highest activity while HiC is significantly more active than other enzymes on 2TBC. The E values of AoC, HiC, TLL, and RML for menthol are 27.8, 16.5, 155, and 125, respectively. HiC has a higher activity (>10-fold) on (-)-2TBC than AoC while they exhibit similar activities on menthol. Docking results reveal that the bulky group adjacent to the hydroxyl group determines the enantioselectivity of AoC, HiC, TLL, and RML. Amino acid residues that dominate the enantioselectivity of these enzymes are AoC's Phe195 aromatic ring; HiC's hydrophobic Leu 174 and Ile 169 groups; TLL's ring structures of Trp89, His258 and Tyr21; and Trp88 for RML. Results of this study highlight that cutinases can provide important advantages relative to lipases for enantioselective transformation, most notably with bulky and sterically hindered substrates.
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Affiliation(s)
- An Su
- New York State Center for Polymer Synthesis, Department of Chemistry and Chemical Biology, Rensselaer Polytechnic Institute, 110 8th Street, Troy, NY 12180, USA; Center for Biotechnology and Interdisciplinary Studies, Department of Biological Sciences, Rensselaer Polytechnic Institute, 1623 15th Street, Troy, NY 12180, USA
| | - Serpil Kiokekli
- Department of Chemistry, University of Crete, Voutes University Campus, 70013 Heraklion, Greece
| | - Mariam Naviwala
- The Howard P. Isermann Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, 110 8th Street, Troy, NY 12180, USA
| | - Abhijit N Shirke
- New York State Center for Polymer Synthesis, Department of Chemistry and Chemical Biology, Rensselaer Polytechnic Institute, 110 8th Street, Troy, NY 12180, USA; Center for Biotechnology and Interdisciplinary Studies, Department of Biological Sciences, Rensselaer Polytechnic Institute, 1623 15th Street, Troy, NY 12180, USA
| | - Ioannis V Pavlidis
- Department of Chemistry, University of Crete, Voutes University Campus, 70013 Heraklion, Greece.
| | - Richard A Gross
- New York State Center for Polymer Synthesis, Department of Chemistry and Chemical Biology, Rensselaer Polytechnic Institute, 110 8th Street, Troy, NY 12180, USA; Center for Biotechnology and Interdisciplinary Studies, Department of Biological Sciences, Rensselaer Polytechnic Institute, 1623 15th Street, Troy, NY 12180, USA.
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Su A, Tyrikos-Ergas T, Shirke AN, Zou Y, Dooley AL, Pavlidis IV, Gross RA. Revealing Cutinases’ Capabilities as Enantioselective Catalysts. ACS Catal 2018. [DOI: 10.1021/acscatal.8b02099] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- An Su
- Department of Chemistry and Chemical Biology, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
- Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
| | - Theodore Tyrikos-Ergas
- Department of Chemistry, University of Crete, Voutes University Campus, 70013 Heraklion, Greece
| | - Abhijit N. Shirke
- Department of Chemistry and Chemical Biology, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
- Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
| | - Yi Zou
- Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
| | - Abigail L. Dooley
- Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
| | - Ioannis V. Pavlidis
- Department of Chemistry, University of Crete, Voutes University Campus, 70013 Heraklion, Greece
| | - Richard A. Gross
- Department of Chemistry and Chemical Biology, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
- Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
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Kamble MP, Chaudhari SA, Singhal RS, Yadav GD. Synergism of microwave irradiation and enzyme catalysis in kinetic resolution of (R,S) -1-phenylethanol by cutinase from novel isolate Fusarium ICT SAC1. Biochem Eng J 2017. [DOI: 10.1016/j.bej.2016.09.007] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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4
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Synthetic application and activity of cutinase in an aqueous, miniemulsion model system: Hexyl octanoate synthesis. Catal Today 2011. [DOI: 10.1016/j.cattod.2011.05.039] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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5
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de Barros DP, Lemos F, Fonseca LP, Cabral JM. Kinetic cutinase-catalyzed esterification of caproic acid in organic solvent system. ACTA ACUST UNITED AC 2010. [DOI: 10.1016/j.molcatb.2010.06.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Branco RJF, Graber M, Denis V, Pleiss JÃ. Molecular Mechanism of the Hydration ofCandida antarcticaLipase B in the Gas Phase: Water Adsorption Isotherms and Molecular Dynamics Simulations. Chembiochem 2009; 10:2913-9. [DOI: 10.1002/cbic.200900544] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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7
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Biosynthesis of ethyl caproate and other short ethyl esters catalyzed by cutinase in organic solvent. ACTA ACUST UNITED AC 2009. [DOI: 10.1016/j.molcatb.2009.05.004] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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8
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Rezaei K, Jenab E, Temelli F. Effects of Water on Enzyme Performance with an Emphasis on the Reactions in Supercritical Fluids. Crit Rev Biotechnol 2008; 27:183-95. [DOI: 10.1080/07388550701775901] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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9
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Karmee SK, Casiraghi L, Greiner L. Technical aspects of biocatalysis in non-CO2-based supercritical fluids. Biotechnol J 2008; 3:104-11. [DOI: 10.1002/biot.200700199] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Hobbs HR, Thomas NR. Biocatalysis in Supercritical Fluids, in Fluorous Solvents, and under Solvent-Free Conditions. Chem Rev 2007; 107:2786-820. [PMID: 17564485 DOI: 10.1021/cr0683820] [Citation(s) in RCA: 213] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Helen R Hobbs
- School of Chemistry, University of Nottingham, University Park, Nottingham, NG7 2RD, United Kingdom
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11
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Abstract
A comprehensive study of the hydration mechanism of an enzyme in nonaqueous media was done using molecular dynamics simulations in five organic solvents with different polarities, namely, hexane, 3-pentanone, diisopropyl ether, ethanol, and acetonitrile. In these solvents, the serine protease cutinase from Fusarium solani pisi was increasingly hydrated with 12 different hydration levels ranging from 5% to 100% (w/w) (weight of water/weight of protein). The ability of organic solvents to 'strip off' water from the enzyme surface was clearly dependent on the nature of the organic solvent. The rmsd of the enzyme from the crystal structure was shown to be lower at specific hydration levels, depending on the organic solvent used. It was also shown that organic solvents determine the structure and dynamics of water at the enzyme surface. Nonpolar solvents enhance the formation of large clusters of water that are tightly bound to the enzyme, whereas water in polar organic solvents is fragmented in small clusters loosely bound to the enzyme surface. Ions seem to play an important role in the stabilization of exposed charged residues, mainly at low hydration levels. A common feature is found for the preferential localization of water molecules at particular regions of the enzyme surface in all organic solvents: water seems to be localized at equivalent regions of the enzyme surface independently of the organic solvent employed.
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Affiliation(s)
- Nuno M Micaêlo
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisoba, Oeiras, Portugal
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12
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Micaêlo NM, Soares CM. Modeling hydration mechanisms of enzymes in nonpolar and polar organic solvents. FEBS J 2007. [DOI: 10.1111/j.0014-2956.2007.05781.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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13
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Influence of the presence of NaY zeolite on the activity of horseradish peroxidase in the oxidation of phenol. ACTA ACUST UNITED AC 2007. [DOI: 10.1016/j.molcatb.2006.08.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Micaelo NM, Teixeira VH, Baptista AM, Soares CM. Water dependent properties of cutinase in nonaqueous solvents: a computational study of enantioselectivity. Biophys J 2005; 89:999-1008. [PMID: 15923226 PMCID: PMC1366647 DOI: 10.1529/biophysj.105.063297] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The catalytic properties of enzymes in nonaqueous solvents are known to be dependent on the nature of the solvent. Here we present a molecular modeling study of the enantioselective properties of the enzyme cutinase in hexane under varying hydration conditions. Previous simulation studies have shown that for this model enzyme in hexane, the structural and dynamical properties are affected by the amount of water associated with the protein, being more similar to the aqueous simulation at 5-10% of water content. The implications of the hydration levels on the enzyme resolution of (R,S)-1-phenylethanol and (R,S)-2-phenyl-1-propanol are investigated using free energy calculations of the tetrahedral intermediate (TI) model. With this model system we show that the enzyme enantioselective properties are under the control of the amount of water present in the organic media. Maximum enantioselectivity is achieved at 10% water content. The stabilizing effects of the catalytic histidine on the TI are evaluated at different water contents and shown to be correlated. The correlation between the amount of water present in the media and the structural, dynamical, and thermodynamic properties of the enzyme are examined as well as the active site discriminative power.
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Affiliation(s)
- Nuno M Micaelo
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal
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15
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16
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Matsuda T, Watanabe K, Harada T, Nakamura K. Enzymatic reactions in supercritical CO2: carboxylation, asymmetric reduction and esterification. Catal Today 2004. [DOI: 10.1016/j.cattod.2004.06.111] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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17
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Bauza R, Rı́os A, Gómez-Hens A, Valcárcel M. Supercritical fluid immunoextraction: a new approach for immunoassay automation. Anal Chim Acta 2004. [DOI: 10.1016/j.aca.2004.05.028] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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18
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Vidinha P, Harper N, Micaelo NM, Lourenco NMT, da Silva MDRG, Cabral JMS, Afonso CAM, Soares CM, Barreiros S. Effect of immobilization support, water activity, and enzyme ionization state on cutinase activity and enantioselectivity in organic media. Biotechnol Bioeng 2004; 85:442-9. [PMID: 14755562 DOI: 10.1002/bit.10780] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We studied the reaction between vinyl butyrate and 2-phenyl-1-propanol in acetonitrile catalyzed by Fusarium solani pisi cutinase immobilized on zeolites NaA and NaY and on Accurel PA-6. The choice of 2-phenyl-1-propanol was based on modeling studies that suggested moderate cutinase enantioselectivity towards this substrate. With all the supports, initial rates of transesterification were higher at a water activity (a(w)) of 0.2 than at a(w) = 0.7, and the reverse was true for initial rates of hydrolysis. By providing acid-base control in the medium through the use of solid-state buffers that control the parameter pH-pNa, which we monitored using an organo-soluble chromoionophoric indicator, we were able, in some cases, to completely eliminate dissolved butyric acid. However, none of the buffers used were able to improve the rates of transesterification relative to the blanks (no added buffer) when the enzyme was immobilized at an optimum pH of 8.5. When the enzyme was immobilized at pH 5 and exhibited only marginal activity, however, even a relatively acidic buffer with a pK(a) of 4.3 was able to restore catalytic activity to about 20% of that displayed for a pH of immobilization of 8.5, at otherwise identical conditions. As a(w) was increased from 0.2 to 0.7, rates of transesterification first increased slightly and then decreased. Rates of hydrolysis showed a steady increase in that a(w) range, and so did total initial reaction rates. The presence or absence of the buffers did not impact on the competition between transesterification and hydrolysis, regardless of whether the butyric acid formed remained as such in the reaction medium or was eliminated from the microenvironment of the enzyme through conversion into an insoluble salt. Cutinase enantioselectivity towards 2-phenyl-1-propanol was indeed low and was not affected by differences in immobilization support, enzyme protonation state, or a(w).
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Affiliation(s)
- Pedro Vidinha
- REQUIMTE/CQFB, Departamento de Quimica, FCT, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal
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19
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Soares CM, Teixeira VH, Baptista AM. Protein structure and dynamics in nonaqueous solvents: insights from molecular dynamics simulation studies. Biophys J 2003; 84:1628-41. [PMID: 12609866 PMCID: PMC1302733 DOI: 10.1016/s0006-3495(03)74972-8] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
Protein structure and dynamics in nonaqueous solvents are here investigated using molecular dynamics simulation studies, by considering two model proteins (ubiquitin and cutinase) in hexane, under varying hydration conditions. Ionization of the protein groups is treated assuming "pH memory," i.e., using the ionization states characteristic of aqueous solution. Neutralization of charged groups by counterions is done by considering a counterion for each charged group that cannot be made neutral by establishing a salt bridge with another charged group; this treatment is more physically reasonable for the nonaqueous situation, contrasting with the usual procedures. Our studies show that hydration has a profound effect on protein stability and flexibility in nonaqueous solvents. The structure becomes more nativelike with increasing values of hydration, up to a certain point, when further increases render it unstable and unfolding starts to occur. There is an optimal amount of water, approximately 10% (w/w), where the protein structure and flexibility are closer to the ones found in aqueous solution. This behavior can explain the experimentally known bell-shaped dependence of enzyme catalysis on hydration, and the molecular reasons for it are examined here. Water and counterions play a fundamental and dynamic role on protein stabilization, but they also seem to be important for protein unfolding at high percentages of bound water.
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Affiliation(s)
- Cláudio M Soares
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República, Apartado 127, 2781-901 Oeiras, Portugal.
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Fontes N, Partridge J, Halling PJ, Barreiros S. Zeolite molecular sieves have dramatic acid-base effects on enzymes in nonaqueous media. Biotechnol Bioeng 2002; 77:296-305. [PMID: 11753938 DOI: 10.1002/bit.10138] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Zeolite molecular sieves very commonly are used as in situ drying agents in reaction mixtures of enzymes in nonaqueous media. They often affect enzyme behavior, and this has been interpreted in terms of altered hydration. Here, we show that zeolites can also have dramatic acid-base effects on enzymes in low water media, resulting from their cation-exchange ability. Initial rates of transesterification catalyzed by cross-linked crystals of subtilisin were compared in supercritical ethane, hexane, and acetonitrile with water activity fixed by pre-equilibration. Addition of zeolite NaA (4 A powder) still caused remarkable rate enhancements (up to 20-fold), despite the separate control of hydration. In the presence of excess of an alternative solid-state acid-base buffer, however, zeolite addition had no effect. The more commonly used Merck molecular sieves (type 3 A beads) had similar but somewhat smaller effects. All zeolites have ion-exchange ability and can exchange H+ for cations such as Na+ and K+. These exchanges will tend to affect the protonation state of acidic groups in the protein and, hence, enzymatic activity. Zeolites pre-equilibrated in aqueous suspensions of varying pH-pNa gave very different enzyme activities. Their differing basicities were demonstrated directly by equilibration with an indicator dissolved in toluene. The potential of zeolites as acid-base buffers for low-water media is discussed, and their ability to overcome pH memory is demonstrated.
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Affiliation(s)
- Nuno Fontes
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Apt. 127, 2781-901 Oeiras, Portugal.
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Matsuda T, Kanamaru R, Watanabe K, Harada T, Nakamura K. Control on enantioselectivity with pressure for lipase-catalyzed esterification in supercritical carbon dioxide. Tetrahedron Lett 2001. [DOI: 10.1016/s0040-4039(01)01785-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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22
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Fontes N, Almeida MC, Garcia S, Peres C, Partridge J, Halling PJ, Barreiros S. Supercritical fluids are superior media for catalysis by cross-linked enzyme microcrystals of subtilisin Carlsberg. Biotechnol Prog 2001; 17:355-8. [PMID: 11312714 DOI: 10.1021/bp000148m] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report on the performance of cross-linked enzyme microcrystals (CLECs) of subtilisin Carlsberg in supercritical fluids (SC-fluids). The catalytic activity of CLECs in SC-ethane was found to be 2- to 10-fold greater than in hexane under the same conditions, using CLECs dried by propanol washing. Air-dried CLECs and lyophilized powders showed much lower activities, reflecting the same hydration hysteresis effects as in organic solvents. Reaction rates were much lower in SC-CO(2), especially at higher water activity, probably as a result of acid-base effects of carbonic acid on the enzyme.
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Affiliation(s)
- N Fontes
- Instituto de Tecnologia Quimica e Biológica, Universidade Nova de Lisboa, Apt. 127, 2781-901 Oeiras, Portugal
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23
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Rees DG, Halling PJ. Chemical modification probes accessibility to organic phase: proteins on surfaces are more exposed than in lyophilized powders. Enzyme Microb Technol 2001; 28:282-292. [PMID: 11166823 DOI: 10.1016/s0141-0229(00)00358-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Chemical modification of myoglobin and cutinase suspended in n-hexane by acyl chlorides and iodine was monitored by electrospray mass spectrometry. The general rate of modification was always much faster for protein adsorbed to supports (silica or polypropylene) than for lyophilized powders. Modification rates were slower for larger acyl chlorides, particularly with lyophilized powders. About 20% of the protein molecules in lyophilized powders were modified much more quickly than the rest, a fraction consistent with those exposed on the surface of the solid. It appears that access to most of the molecules in lyophilized powders requires a very slow stage of solid-phase diffusion. This has been neglected in previous discussion of mass transfer limitation of lyophilized enzymes in organic media, and would not be revealed by the experimental evidence used to dismiss it. Studies of the effects of particle size and dilution with inactive protein are only sensitive to diffusion in liquid-filled pores, not through the solid phase. Slow solid-phase diffusion is not required for access to most support-adsorbed proteins, which is probably a major contributory factor to their enhanced catalytic efficiency in organic media. Hydration of lyophilized proteins accelerates chemical modification rates, as it does their catalytic activity. The main site of reaction of acyl chlorides in organic media is not amino groups (which are probably ion-paired), but is likely to be hydroxyl groups instead.
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Affiliation(s)
- D G. Rees
- Departments of Bioscience and Biotechnology and Pure and Applied Chemistry, University of Strathclyde, G1 1XW, Glasgow, UK
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24
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Enantioselective properties of Fusarium solani pisi cutinase on transesterification of acyclic diols: activity and stability evaluation. ACTA ACUST UNITED AC 2001. [DOI: 10.1016/s1381-1177(00)00072-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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25
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Chemical modification probes accessibility to organic phase: proteins on surfaces are more exposed than in lyophilized powders. Enzyme Microb Technol 2000; 27:549-559. [PMID: 11024517 DOI: 10.1016/s0141-0229(00)00240-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Chemical modification of myoglobin and cutinase suspended in n-hexane by acyl chlorides and iodine was monitored by electrospray mass spectrometry. The general rate of modification was always much faster for protein adsorbed to supports (silica or polypropylene) than for lyophilized powders. Modification rates were slower for larger acyl chlorides, particularly with lyophilized powders. About 20% of the protein molecules in lyophilized powders were modified much more quickly than the rest, a fraction consistent with those exposed on the surface of the solid. It appears that access to most of the molecules in lyophilized powders requires a very slow stage of solid-phase diffusion. This has been neglected in previous discussion of mass transfer limitation of lyophilized enzymes in organic media, and would not be revealed by the experimental evidence used to dismiss it. Studies of the effects of particle size and dilution with inactive protein are only sensitive to diffusion in liquid-filled pores, not through the solid phase. Slow solid-phase diffusion is not required for access to most support-adsorbed proteins, which is probably a major contributory factor to their enhanced catalytic efficiency in organic media. Hydration of lyophilized proteins accelerates chemical modification rates, as it does their catalytic activity. The main site of reaction of acyl chlorides in organic media is not amino groups (which are probably ion-paired), but is likely to be hydroxyl groups instead.
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Abstract
This review analyzes the role of cutinases in nature and their potential biotechnological applications. The cloning and expression of a fungal cutinase, Fusarium solani f. pisi, in Escherichia coli and Saccharomyces cerevisiae hosts are described. The three-dimensional structure of this cutinase is also analyzed and its function as a lipase is discussed and compared with other lipases. The biocatalytic applications of cutinase are described taking into account the preparation of different cutinase forms and the media in which the different types of reactions have been performed, namely hydrolysis, esterification, transesterification, and resolution of racemic mixtures. The stability of cutinase preparations is discussed and, in particular, the cutinase stability in anionic reversed micelles is analyzed considering the role of hexanol as a substrate, a cosurfactant, and a stabilizer. Process development, based on the operation of cutinase reactors, is also reviewed.
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Affiliation(s)
- C M Carvalho
- Centro de Engenharia Biológica e Química, Instituto Superior Técnico, 1049-001 Lisboa, Portugal
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27
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