Kita K, Ishimaru K, Teraoka M, Yanase H, Kato N
Department of Biotechnology, Tottori University, Japan.
Appl Environ Microbiol. 1995 May;61(5):1727-30. doi: 10.1128/aem.61.5.1727-1730.1995.
Alcaligenes faecalis AE122 that used poly(3-hydroxybutyrate) (PHB) as a sole source of carbon was newly isolated from a coastal seawater sample. The strain required seawater for growth on PHB as well as in a nutrient broth, in which seawater could be replaced by an appropriate concentration of NaCl. PHB depolymerase was purified to homogeneity from the culture supernatant of A. faecalis AE122 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The enzyme consisted of a monomer subunit with a molecular mass of 95.5 kDa. The N-terminal amino acid sequence was GAWQNNLAGGFNKV. The dimeric and trimeric esters of 3-hydroxybutyrate were the main hydrolysis products of the purified enzyme. The enzyme was most active at pH 9.0 and 55 degrees C and was inhibited by phenylmethylsulfonyl fluoride. Several cations in seawater greatly enhanced the enzyme activity.
从沿海海水样本中新分离出一株粪产碱菌AE122，它能够利用聚（3-羟基丁酸酯）（PHB）作为唯一碳源。该菌株在以PHB为碳源生长时以及在营养肉汤中生长时都需要海水，在营养肉汤中海水可用适当浓度的氯化钠替代。通过十二烷基硫酸钠-聚丙烯酰胺凝胶电泳从粪产碱菌AE122的培养上清液中纯化得到了具有均一性的PHB解聚酶。该酶由一个分子量为95.5 kDa的单体亚基组成。N端氨基酸序列为GAWQNNLAGGFNKV。3-羟基丁酸的二聚体和三聚体酯是纯化酶的主要水解产物。该酶在pH 9.0和55℃时活性最高，并且受到苯甲基磺酰氟的抑制。海水中的几种阳离子可大大提高该酶活性。
