Identification of the Intracellular Polyhydroxyalkanoate Depolymerase Gene of Paracoccus Denitrificans and Some Properties of the Gene Product

FEMS Microbiol Lett. 2001 Mar 15;196(2):159-64. doi: 10.1111/j.1574-6968.2001.tb10558.x.


Paracoccus denitrificans degraded poly(3-hydroxybutyrate) (PHB) in the cells under carbon source starvation. Intracellular poly(3-hydroxyalkanoate) (PHA) depolymerase gene (phaZ) was identified near the PHA synthase gene (phaC) of P. denitrificans. Cell extract of Escherichia coli carrying lacZ--phaZ fusion gene degraded protease-treated PHB granules. Reaction products were thought to be mainly D(--)-3-hydroxybutyrate (3HB) dimer and 3HB oligomer. Diisopropylfluorophosphonate and Triton X-100 exhibited an inhibitory effect on the degradation of PHB granules. When cell extract of the recombinant E. coli was used, Mg(2+) ion inhibited PHB degradation. However, the inhibitory effect by Mg(2+) ion was not observed using the cell extract of P. denitrificans.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Base Sequence
  • Biodegradation, Environmental
  • Carboxylic Ester Hydrolases / genetics*
  • Carboxylic Ester Hydrolases / isolation & purification
  • Cloning, Molecular
  • DNA, Bacterial
  • Escherichia coli
  • Genes, Bacterial
  • Hydroxybutyrates / metabolism
  • Indicators and Reagents
  • Magnesium / metabolism
  • Molecular Sequence Data
  • Paracoccus denitrificans / enzymology*
  • Paracoccus denitrificans / genetics
  • Polyesters / metabolism
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / metabolism


  • DNA, Bacterial
  • Hydroxybutyrates
  • Indicators and Reagents
  • Polyesters
  • Recombinant Proteins
  • Carboxylic Ester Hydrolases
  • poly(3-hydroxyalkanoic acid) depolymerase
  • Magnesium