Substrate specificity of alpha-chymotrypsin-catalyzed esterification in organic media.
Biochim Biophys Acta
; 1118(1): 70-6, 1991 Dec 11.
Article
em En
| MEDLINE
| ID: mdl-1764479
ABSTRACT
11 amino acid derivatives were tested as alpha-chymotrypsin substrates in the esterification reaction with methanol in organic media. The reactions were carried out in water-saturated ethyl acetate and in acetonitrile containing 4% water. alpha-Chymotrypsin adsorbed on Celite was used as a catalyst. From initial reaction rate measurements, the Michaelis-Menten parameters Vmax and KM were determined. All the amino acid derivatives tested were esterified, and the highest values of kcat/KM were obtained with the N-acylated aromatic amino acids. Correlations between Michaelis-Menten parameters and physical properties of the substrates such as molar refractivity (MR) and log P were deduced. The results show that the specificity of the alpha-chymotrypsin towards the side chain of the amino acids in organic media is the same as that in aqueous media. However, the specificity towards the N-protecting group is opposite to that in water, so the reaction medium affects the interaction of this part of the molecule with the enzyme to a large extent.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Quimotripsina
Limite:
Animals
Idioma:
En
Revista:
Biochim Biophys Acta
Ano de publicação:
1991
Tipo de documento:
Article
País de afiliação:
Suécia