| Autor: |
Kleeberg, I., Welzel, K., Heuvel, J. van den, Muller, R.-J., Deckwer, W.-D. |
| Zdroj: |
Biomacromolecules; January 2005, Vol. 6 Issue: 1 p262-270, 9p |
| Abstrakt: |
The paper describes the purification, biochemical characterization, sequence determination, and classification of a novel thermophilic hydrolase from Thermobifida fusca (TfH) which is highly active in hydrolyzing aliphatic−aromatic copolyesters. The secretion of the extracellular enzyme is induced by the presence of aliphatic−aromatic copolyesters but also by adding several other esters to the medium. The hydrophobic enzyme could be purified applying a combination of (NH4)SO4-precipitation, cation-exchange chromatography, and hydrophobic interaction chromatography. The 28 kDa enzyme exhibits a temperature maximum of activity between 65 and 70 °C and a pH maximum between pH 6 and 7 depending on the ion strength of the solution. According to the amino sequence determination, the enzyme consists of 261 amino acids and was classified as a serine hydrolase showing high sequence similarity to a triacylglycerol lipase from Streptomyces albus G and triacylglycerol-aclyhydrolase from Streptomyces sp. M11. The comparison with other lipases and esterases revealed the TfH exhibits a catalytic behavior between a lipase and an esterase. Such enzymes often are named as cutinases. However, the results obtained here show, that classifying enzymes as cutinases seems to be generally questionable. |
| Databáze: |
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