| Title | Purification and Characterization of Extracellular Poly(3-hydroxybutyrate) Depolymerase from Penicillium simplicissimum LAR13 |
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| Author | Jee-Sun Han and Mal-Nam Kim * |
| Address | Department of Biology, Sangmyung University, Seoul, 110-743 Korea |
| Bibliography | Journal of Microbiology, 40(1),20-25, 2002, |
| DOI | |
| Key Words | depolymerase, Penicillium simplicissimum, poly(3-hydroxybutyrate) |
| Abstract | An extracellular PHB depolymerase was purified from P. simplicissimum LAR13 cultural medium by Sepharose CL-6B chromatography. When the fungus was grown in a basal salt medium with poly(3-hydroxybutyrate) (PHB) as the sole carbon source, PHB depolymerase production reached maximum at its stationary phase. The mycelial growth rate was higher at 37 C than at 30 C and even higher than at 25 C, However, the enzyme production was lower at 37 C than 30 C or 25 C. The isolated enzyme is composed of a single polypeptide chain with a molecular mass of about 36 kDa as determined by SDS-PAGE. The optimum conditions for the enzyme activity are pH 5.0 and 45 C. The enzyme was stable for 30 min at a temperature lower than 50 C, and stable at pH higher than 2.0 but it was unstable at pH 1.0. 1 mM Fe^2+ reduced the enzyme activity by 56% and the enzyme was inhibited almost completely by 4 mM Fe^2+ . The enzyme was partially inhibited by phenylmethylsulfonyl fluoride and was very sensitive to diazo-DL-norleucine methyl ester, dithiothreitol and mercuric ion. However, N-p-tosyl-L-lysinechloromethyl ketone, p-hydroxymercuricbenzoate and N-acetylimidazole had no influence upon its activity. |
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