title: Partial purification and characterization of a novel histidine decarboxylase from Enterobacter aerogenes DL-1.
abstract: Histidine decarboxylase (HDC) from Enterobacter aerogenes DL-1 was purified in a three-step procedure involving ammonium sulfate precipitation, Sephadex G-100, and DEAE-Sepharose column chromatography. The partially purified enzyme showed a single protein band of 52.4 kD on sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The optimum pH for HDC activity was 6.5, and the enzyme was stable between pH 4 and 8. Enterobacter aerogenes HDC had optimal activity at 40°C and retained most of its activity between 4 and 50°C. HDC activity was reduced in the presence of numerous tested compounds. Particularly with SDS, it significantly (p < 0.01) inhibited enzyme activity. Conversely, Ca(2+) and Mn(2+) showed prominent activation effects (p < 0.01) with activity increasing to 117.20% and 123.42%, respectively. The Lineweaver-Burk plot showed that K m and V max values of the enzyme for L-histidine were 0.21 mM and 71.39 µmol/min, respectively. In comparison with most HDCs from other microorganisms and animals, HDC from E. aerogenes DL-1 displayed higher affinity and greater reaction velocity toward L-histidine.
authors.affiliation: a College of Life Science , Dalian Nationalities University , Dalian , China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Zou
authors.forename: Wenzhong
authors.initials: W
authors.lastname: Hu
authors.forename: Aili
authors.initials: A
authors.lastname: Jiang
authors.forename: Mixia
authors.initials: M
authors.lastname: Tian
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002848:Chromatography, DEAE-Cellulose / Q000379:methods*; D021902:Enterobacter aerogenes / Q000145:classification* / Q000201:enzymology*; D004789:Enzyme Activation; D004795:Enzyme Stability; D005590:Fractional Precipitation / Q000379:methods*; D006640:Histidine Decarboxylase / Q000737:chemistry* / Q000302:isolation & purification* / Q000378:metabolism; D008969:Molecular Sequence Data; D010473:Perciformes / Q000382:microbiology*; D013045:Species Specificity
chemical_list: D006640:Histidine Decarboxylase
keywords: Enterobacter aerogenes; characterization; histidine decarboxylase; purification