ISSN:
0006-3592
Keywords:
agarose-chymotrypsin
;
enzymes in organic media
;
esterification
;
peptide synthesis
;
Chemistry
;
Biochemistry and Biotechnology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Biology
,
Process Engineering, Biotechnology, Nutrition Technology
Notes:
The synthesis of N-acetyl tryptophan phenylethyl ester in organic media is catalyzed by suspended agarose beads with multipoint covalently attached chymotrypsin. A dilute aqueous phase is trapped within the gel beads and may be manipulated separately from the organic phase. The equilibrium position becomes more favorable as the solvent polarity decreases, with Keq increasing 38 times between 2-butanone and 1,1,1-trichloroethane. The more apolar solvents also give faster kinetics. Addition of cosolvents (up to 10% dimethylformamide or 20% acetonitrile) does not affect the rate but does substantially reduce the equilibrium yield, presumably also by making the organic phase more polar. With trichloroethane as solvent the enzyme appears to be kinetically saturated with 1M phenylethanol. Doubling this concentration also does not cause the expected increase in equilibrium conversion, probably again because Keq is reduced in the more polar organic phase. Increased temperature raises the reaction rate as expected but has little effect on the equilibrium. © 1992 John Wiley & Sons, Inc.
Additional Material:
4 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/bit.260400913
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