Purification and properties of a poly (β-hydroxybutyrate) depolymerase from penicillium sp.
Date
2006
Authors
Liu, H.
Zhang, H.
Chen, S.
Liu, D.
Xia, H.
Editors
Advisors
Journal Title
Journal ISSN
Volume Title
Type:
Journal article
Citation
Journal of Polymers and the Environment, 2006; 14(4):419-426
Statement of Responsibility
Hongyu Liu, Hu Zhang, Shan Chen, Dongbo Liu and Hongmei Xia
Conference Name
Abstract
An extracellular poly (β-hydroxybutyrate) (PHB) depolymerase was purified from a Penicillium sp. DS9701-09a by centrifugation, ultrafiltration, precipitation and gel filtration chromatography. The specific activity of the purified enzyme was 37.9-folds higher than that of the culture supernatant and the recovery yield was 11.8%. The PHB deploymerase molecular mass was 44.8 kDa from analysis of both Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and Matrix-assisted laser desorption-time-of-flight (MALDI-TOF) mass spectrometer. The isoelectric point of 6.7 for the enzyme was determined by a two-dimensional electrophoresis. The optimum enzyme activity was observed at a temperature of 50 °C and pH 5.0. The apparent K m of the enzyme was found to be 1.35 mg/mL. The PHB depolymerase consisted of 16 kinds of normal amino acids. The secondary structure of the enzyme was determined by CD spectrum. α-helix and β-turn were found to be 66% and 34% for the enzyme without ammonium sulphite. Chemical inhibition on the PHB depolymerase activity was examined and EDTA was found to have a significantly inhibitory effect.