title: Roles of poly(3-hydroxybutyrate) depolymerase and 3HB-oligomer hydrolase in bacterial PHB metabolism.
abstract: Many poly-3-hydroxybutyrate (PHB)-degrading enzymes have been studied. But biological roles of 3HB-oligomer hydrolases (3HBOHs) and how PHB depolymerases (PHBDPs) and 3HBOHs cooperate in PHB metabolism are not fully elucidated. In this study, several PHBDPs and 3HBOHs from three types of bacteria were purified, and their substrate specificity, kinetic properties, and degradation products were investigated. From the results, PHBDP and 3HBOH seemed to play a role in PHB metabolism in three types of bacteria, as follows: (A) In Ralstonia pickettii T1, an extracellular PHBDP degrades extracellular PHB to various-sized 3HB-oligomers, which an extracellular 3HBOH hydrolyzes to 3HB-monomers. (B) In Acidovorax sp. SA1, an extracellular PHBDP hydrolyzes extracellular PHB to small 3HB-oligomers (dimer and trimer), which an intracellular 3HBOH efficiently degrades to 3HB in the cell. (C) In Ralstonia eutropha H16, an intracellular 3HBOH helps in the degradation of intracellular PHB inclusions by PHBDP.
authors.affiliation: Laboratory of Molecular Microbiology, Department of Biological Sciences, Faculty of Science, Kanagawa University, Tsuchiya 2946, Hiratsuka, Kanagawa, 259-1293, Japan.
authors.forename: Akinori
authors.initials: A
authors.lastname: Sugiyama
authors.forename: Teruyuki
authors.initials: T
authors.lastname: Kobayashi
authors.forename: Mari
authors.initials: M
authors.lastname: Shiraki
authors.forename: Terumi
authors.initials: T
authors.lastname: Saito
mesh_terms: D020155:3-Hydroxybutyric Acid / Q000378:metabolism; D001419:Bacteria / Q000201:enzymology* / Q000378:metabolism; D002265:Carboxylic Ester Hydrolases / Q000302:isolation & purification / Q000378:metabolism*; D042621:Comamonadaceae / Q000201:enzymology / Q000378:metabolism; D020118:Cupriavidus necator / Q000201:enzymology / Q000378:metabolism; D006885:Hydroxybutyrates / Q000378:metabolism*; D007700:Kinetics; D011091:Polyesters / Q000378:metabolism*; D043367:Ralstonia / Q000201:enzymology / Q000378:metabolism; D013379:Substrate Specificity; D000094122:Polyhydroxybutyrates
chemical_list: D020155:3-Hydroxybutyric Acid; D002265:Carboxylic Ester Hydrolases; D006885:Hydroxybutyrates; D011091:Polyesters; C003182:poly-beta-hydroxybutyrate; D000094122:Polyhydroxybutyrates; C022417:poly-beta-hydroxybutyrate depolymerase; C032152:hydroxybutyrate-dimer hydrolase