Gao D, Maehara A, Yamane T, Ueda S
Departmentof Bioproductive Science, Faculty of Agriculture, Utsunomiya University, Japan.
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.
在碳源饥饿条件下，反硝化副球菌在细胞内降解聚（3-羟基丁酸酯）（PHB）。在反硝化副球菌的聚（3-羟基链烷酸酯）（PHA）合酶基因（phaC）附近鉴定到了细胞内聚（3-羟基链烷酸酯）解聚酶基因（phaZ）。携带lacZ-phaZ融合基因的大肠杆菌细胞提取物可降解经蛋白酶处理的PHB颗粒。反应产物被认为主要是D（-）-3-羟基丁酸酯（3HB）二聚体和3HB寡聚体。二异丙基氟磷酸酯和吐温X-100对PHB颗粒的降解具有抑制作用。当使用重组大肠杆菌的细胞提取物时，Mg（2+）离子会抑制PHB的降解。然而，使用反硝化副球菌的细胞提取物时未观察到Mg（2+）离子的抑制作用。
