title: [Gene cloning, expression and characterization of a novel phytase from Hafnia alvei].
abstract: A gene appA encoding a novel phytase was firstly cloned from Hafnia alvei by PCR and sequenced. The gene was consisted of 1335 bp, encoding 444 amino acids. The calculated molecular weight of the mature APPA was about 45.2 kD. The gene appA was expressed in E. coli BL21 (DE3). Recombinant APPA was purified and its enzymatic properties were determined. The optimum pH for the enzyme was 4.5 and the optimum temperature was 60 degrees C. The pH stability of r-APPA is good, the relative phytase activity was above 80% after treated in buffers of pH 2.0-10.0. The specific activity of r-APPA is 356.7 U/mg, and the Km value was 0.49 mmol/L and Vmax of 238 U/mg. The enzyme showed resistance to pepsin and trypsin treatment.
authors.affiliation: Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
authors.forename: Wei-Na
authors.initials: WN
authors.lastname: Gu
authors.forename: Huo-Qing
authors.initials: HQ
authors.lastname: Huang
authors.forename: Pei-Long
authors.initials: PL
authors.lastname: Yang
authors.forename: Hui-Ying
authors.initials: HY
authors.lastname: Luo
authors.forename: Kun
authors.initials: K
authors.lastname: Meng
authors.forename: Ya-Ru
authors.initials: YR
authors.lastname: Wang
authors.forename: Bin
authors.initials: B
authors.lastname: Yao
mesh_terms: D010832:6-Phytase / Q000096:biosynthesis / Q000235:genetics* / Q000302:isolation & purification; D000595:Amino Acid Sequence; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D020595:Hafnia / Q000201:enzymology* / Q000235:genetics*; D006863:Hydrogen-Ion Concentration; D008969:Molecular Sequence Data; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D013696:Temperature
chemical_list: D011994:Recombinant Proteins; D010832:6-Phytase