Cellulases as chiral selectors

Isaksson, Roland; Pettersson, Curt; Pettersson, Göran; Jónsson, S.; Stålberg, Jerry; Hermansson, Jörgen; Marle, Ingrid

doi:10.1016/0165-9936(94)85024-0

Cited by 37 publications

(39 citation statements)

References 31 publications

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“…CSPs containing trypsin [219] and a-chymotrypsin [220] as chiral selectors showed enantioselectivity for amino acids and derivatives, dipeptides and aryloxypropionic acids [219,221]. Two cellobiohydrolases, CBH I and CBH II [222] and more recently CBH 58 [223], found application as chiral selectors for the preparation of silica-based CSPs which showed remarkable enantioselectivity for a broad spectrum of drugs, among them b-blockers [224]. Lysozyme [225]-and pepsin [226]-based CSPs showed enantioselectivity for basic and neutral enantiomers but not for acidic enantiomers.…”

Section: Chiral Imprinted Polymersmentioning

confidence: 99%

Chiral separation by chromatographic and electromigration techniques. A Review

Gübitz

Schmid

2001

Biopharm & Drug Disp

225

135

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This review gives a survey of different chiral separation principles and their use in high-performance liquid chromatography (HPLC), gas chromatography (GC), supercritical fluid chromatography (SFC), thin-layer chromatography (TLC), capillary electrophoresis (CE) and capillary electrochromatography (CEC) highlighting new developments and innovative techniques. The mechanisms of the different separation principles are briefly discussed and some selected applications are shown.

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Section: Chiral Imprinted Polymersmentioning

confidence: 99%

Chiral separation by chromatographic and electromigration techniques. A Review

Gübitz

Schmid

2001

Biopharm & Drug Disp

225

135

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“…CBH 1 has been found to be an excellent chiral selector and its properties were recently reviewed [9]. It can be coupled to a solid support (silica or continuous bed) [l(L12] to form a chiral stationary phase (CSP) or used in a carrier-free solution in capillary electrophoresis [13].…”

Section: Introductionmentioning

confidence: 99%

The active sites of cellulases are involved in chiral recognition: a comparison of cellobiohydrolase 1 and endoglucanase 1

et al. 1996

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The cellulases ceHobiohydrolase 1 (CBH 1) and endoglucanase 1 (EG 1) from the fungus Trichoderma reesei are closely related with 40% sequence identity and very similar in structure. In CBH 1 the active site is enclosed by long loops and some antiparallel ~strands forming a 40 A long tunnel, whereas in EG 1 part of those loops are missing so that the enzyme has a more common active site groove. Both enzymes were immobilized on silica and these materials were used as chiral stationary phases for chromatographic separation of the enantiomers of two chiral drugs, propranolol and alprenolol. The CBH 1 phase showed much better resolution than did the EG 1 phase, suggesting that the tunnel structure of the protein may play an important role in the chiral separation. The chiral compounds were found to be competitive inhibitors of both enzymes when p-nitrophenyl lactoside (pNPL) was used as substrate. (S)-enantiomers showed stronger inhibitory effects and also longer retention time on the stationary phases than the (R)-enantiomers. The consistency between kinetic data and retention on the stationary phases clearly shows that the enzymatically active sites of CBH 1 and EG 1 are involved in chiral recognition.

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“…[11][12][13] A few retention models have been proposed to explain the effect of the mobile phase composition on the stereoselective retention to the a,-acid glycoprotein phase. l4*I5 The enantiomers were then assumed to be distributed in charged or uncharged form to one or two adsorption sites on the protein molecule.…”

Section: Resultsmentioning

confidence: 99%

Retention model for the resolved enantiomers of felodipine on chiral‐AGP using micellar mobile phases

1995

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A retention model for the chiral separation of an uncharged solute, felodipine, on CHIRAL-AGP, using a micellar mobile phase is proposed. The model assumes the presence of two stereoselective sites and each enantiomer was found to interact with different sites. Addition of a chiral aliphatic alcohol, (+)-(S)-2-octanol, preferentially interacted with the binding site for (-)-(S)-felodipine. The monomeric form of the micellar agent (Tween@ 20) competed with the enantiomers for the adsorption sites, and the formation of a 1: 1 complex between the enantiomers and the micelles was assumed. The retention of the solutes was effectively controlled by adding small quantities (c1.63 x lop3 M) of the nonionic detergent Tween 20 to the mobile phase. Baseline separation was achieved by addition of 1.0 mM n-octylamine to the mobile phase; 8.14 x M Tween 20 in phosphate buffer pH 7.0. The separation factor (a = 1.74) was unaffected by the detergent concentration in the presence of 1.0 d n-octylamine. 0 1995 Wdey-Liss, Inc. KEY WORDS: felodipine, retention model, micellar mobile phases, chiral resolution, CHIRAL-AGPThe enantiomeric resolutions of three hydrophobic amines' and an acid2 using Tween@ 20 as an organic modifier along with different charged additives on a,-acid glycoprotein columns have been described previously. The experiments were typically performed by decreasing the retention time by addition of increasing concentrations of a detergent, and thereafter adding a suitable counterion in order to increase the enantioselectivity. This protocol proved to be particularly useful for the hydrophobic enantiomers studied as it gave short retention times with maintained stereoselectivity. Organic solvents like methanol or acetonitrile have been used extensively as mobile phase modifiers in order to shorten retention times andor give better peak shape. Unfortunately, the presence of high concentrations of uncharged modifiers usually ruins the stereoselectivity, and thus the usefulness of this approach is limited when deahng with highly retained solutes.Although the mechanism of c k a l recognition by the protein is largely unknown, a retention model study can give a general conception of the main types of solute-micelle-protein interactions involved. In order to simplify the system, an aprotic solute, felodipine, was chosen as a test substance for evaluation of the retention model.In 1964 Hemes et al. developed an equation which described the elution of a small solute on a Sephadex G-25 column with a micellar mobile phase.3 The derivation outlined closely followed the classical work of Martin and Synge on partition chromatography4 and also accounted for molecular sieving and micelle partitioning effects. In 1981 Armstrong and Nome introduced the three-phase model for micellar liquid chromatography and also treated the relationship between 0 1995 Wdey-Liss, Inc.solute retention and micellar mobile phase cornpositi~n.~ Later Arunyanart and Cline Love' modelled the retention equation in the form of binding constants and ...

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Cellulases as chiral selectors

Cited by 37 publications

References 31 publications

Chiral separation by chromatographic and electromigration techniques. A Review

Chiral separation by chromatographic and electromigration techniques. A Review

The active sites of cellulases are involved in chiral recognition: a comparison of cellobiohydrolase 1 and endoglucanase 1

Retention model for the resolved enantiomers of felodipine on chiral‐AGP using micellar mobile phases

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