title: Characterization of a new extracellular hydrolase from Thermobifida fusca degrading aliphatic-aromatic copolyesters.
abstract: 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 (NH(4))SO(4)-precipitation, cation-exchange chromatography, and hydrophobic interaction chromatography. The 28 kDa enzyme exhibits a temperature maximum of activity between 65 and 70 degrees 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.
authors.affiliation: Gesellschaft für biotechnologische Forschung mbH, D-38124 Braunschweig, Germany.
authors.forename: I
authors.initials: I
authors.lastname: Kleeberg
authors.forename: K
authors.initials: K
authors.lastname: Welzel
authors.forename: J
authors.initials: J
authors.lastname: Vandenheuvel
authors.forename: R-J
authors.initials: RJ
authors.lastname: Müller
authors.forename: W-D
authors.initials: WD
authors.lastname: Deckwer
mesh_terms: D000192:Actinomycetales / Q000201:enzymology*; D000595:Amino Acid Sequence; D001673:Biodegradation, Environmental; D006863:Hydrogen-Ion Concentration; D006867:Hydrolases / Q000737:chemistry* / Q000145:classification / Q000302:isolation & purification; D008969:Molecular Sequence Data; D011091:Polyesters / Q000737:chemistry*; D013696:Temperature; D013997:Time Factors
chemical_list: D011091:Polyesters; D006867:Hydrolases