title: Purification and characterization of novel extracellular cholesterol esterase from Acinetobacter sp.
abstract: CHE4-1, a bacterial strain that belongs to the genus Acinetobacter and expresses high level of inducible extracellular cholesterol esterase (CHE), was isolated from feces of carnivore Panthera pardus var. The cholesterol esterase of the strain CHE4-1 was purified by ultrafiltration followed with DEAE-Sepharose FF chromatography and Phenyl-Sepharose CL-4B chromatography, and then by Sephadex G-50 gel filtration. Different from other known microbial cholesterol esterase, the purified CHE from CHE4-1 strain is a monomer with molecular weight of 6.5 kD and has high activity to both long-chain and short-chain cholesterol ester. Enzymatic activity was enhanced in the presence of metal ion Ca(2+), Zn(2+) and boracic acid, and was not significantly affected by several detergents including sodium cholate, Triton X100 and Tween-80. The enzyme was found to be stable during long-term aqueous storage at 4 °C, indicating its potential as a clinical diagnostic reagent. To the best of our knowledge, this is the first report regarding purification and characterization of CHE from Acinetobacter sp. The results demonstrated that this particular CHE is a novel cholesterol esterase.
authors.affiliation: College of Life Sciences, Sichuan Normal University, Chengdu, P.R. China.
authors.forename: Liangjun
authors.initials: L
authors.lastname: Du
authors.forename: Ying
authors.initials: Y
authors.lastname: Huo
authors.forename: Fanglan
authors.initials: F
authors.lastname: Ge
authors.forename: Jiajun
authors.initials: J
authors.lastname: Yu
authors.forename: Wei
authors.initials: W
authors.lastname: Li
authors.forename: Guiying
authors.initials: G
authors.lastname: Cheng
authors.forename: Bin
authors.initials: B
authors.lastname: Yong
authors.forename: Lihuang
authors.initials: L
authors.lastname: Zeng
authors.forename: Min
authors.initials: M
authors.lastname: Huang
mesh_terms: D000150:Acinetobacter / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification; D000818:Animals; D004795:Enzyme Stability; D005243:Feces / Q000382:microbiology; D008970:Molecular Weight; D046009:Panthera / Q000382:microbiology; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D002787:Sterol Esterase / Q000302:isolation & purification* / Q000378:metabolism; D013379:Substrate Specificity
chemical_list: D012336:RNA, Ribosomal, 16S; D002787:Sterol Esterase