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Characterization of an extracellular medium-chain-length poly(3-hydroxyalkanoate) depolymerase from Streptomyces sp. KJ-72.

Hwa Jung Kim·Do Young Kim·Jin Sik Nam·Kyung Sook Bae·Young Ha Rhee
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Abstract

A bacterial strain capable of degrading medium-chain-length polyhydroxyalkanoates (MCL-PHAs) was isolated from a soil sample. This organism, which was identified as Streptomyces sp. KJ-72, secreted MCL-PHA depolymerase into the culture fluid only when it was cultivated on MCL-PHAs. The extracellular MCL-PHA depolymerase of the organism was purified to electrophoretic homogeneity by ion exchange column chromatography and gel filtration. The enzyme consisted of a monomeric subunit having a molecular mass of 27.1 kDa and isoelectric point of 4.7. The maximum activity was observed at pH 8.7 and 50 degrees C. The enzyme was sensitive to N-bromosuccinimide and acetic anhydride, indicating the presence of tryptophan and lysine residues in the catalytic domain. The enzyme was able to hydrolyze various chain-length p-nitrophenyl esters of fatty acids and polycaprolactone as well as various types of MCL-PHAs. However, lipase activity of the enzyme was not detected. The main hydrolysis product of poly(3-hydroxyheptanoate) was identified to be the dimer of 3-hydroxyheptanoate.

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Carboxylic Ester HydrolasesCulture MediaDNA, RibosomalMolecular Sequence DataPolyestersRNA, Ribosomal, 16SSequence Analysis, DNASoil MicrobiologyStreptomycesSubstrate SpecificityJournal ArticleResearch Support, Non-U.S. Gov't

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Hwa Jung Kim, Do Young Kim, Jin Sik Nam, Kyung Sook Bae, Young Ha Rhee. 2003. Characterization of an extracellular medium-chain-length poly(3-hydroxyalkanoate) depolymerase from Streptomyces sp. KJ-72.. https://doi.org/10.1023/a%3A1023395527073

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