Further kinetic and molecular characterization of an extremely heat-stable carboxylesterase from the thermoacidophilic archaebacterium Sulfolobus acidocaldarius

The carboxylesterase (serine esterase, EC 3.1.1.1) from Sulfolobus acidocaldarius was purified 940-fold to homogeneity by an improved purification procedure with a yield of 57%. In the presence of alcohols the enzyme catalyses the transfer of the substrate acyl group to alcohols in parallel to hydro...

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Bibliographic Details
Published in:Biochemical journal 1989-08, Vol.261 (3), p.993-998
Main Authors: Sobek, H, Görisch, H
Format: Article
Language:English
Subjects:
Amino Acid Sequence
Archaea - enzymology
Bacteria - enzymology
carboxylesterase
Catalysis
Esterases - isolation & purification
Esterases - metabolism
Kinetics
Molecular Sequence Data
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Summary:The carboxylesterase (serine esterase, EC 3.1.1.1) from Sulfolobus acidocaldarius was purified 940-fold to homogeneity by an improved purification procedure with a yield of 57%. In the presence of alcohols the enzyme catalyses the transfer of the substrate acyl group to alcohols in parallel to hydrolysis. The results show the existence of an alcohol-binding site and a competitive partitioning of the acyl-enzyme intermediate between water and alcohols. Aniline acts also as a nucleophilic acceptor for the acyl group. On the basis of titration with diethyl p-nitrophenyl phosphate, a number of four active centres is determined for the tetrameric carboxylesterase. The sequence of 20 amino acid residues at the esterase N-terminus and the amino acid composition are reported.
ISSN:0264-6021
1470-8728
DOI:10.1042/bj2610993