title: Purification and characterization of agarases from a marine bacterium Vibrio sp. F-6.
abstract: Marine bacterium Vibrio sp. F-6, utilizing agarose as a carbon source to produce agarases, was isolated from seawater samples taken from Qingdao, China. Two agarases (AG-a and AG-b) were purified to a homogeneity from the cultural supernatant of Vibrio sp. F-6 through ammonium sulfate precipitation, Q-Sepharose FF chromatography, and Sephacryl S-100 gel filtration. Molecular weights of agarases were estimated to be 54.0 kDa (AG-a) and 34.5 kDa (AG-b) by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The optimum pH values for AG-a and AG-b were about 7.0 and 9.0, respectively. AG-a was stable in the pH range of 4.0-9.0 and AG-b was stable in the pH range of 4.0-10.0. The optimum temperatures of AG-a and AG-b were 40 and 55 degrees C, respectively. AG-a was stable at temperature below 50 degrees C. AG-b was stable at temperature below 60 degrees C. Zn(2+), Mg(2+) or Ca(2+) increased AG-a activity, while Mn(2+), Cu(2+) or Ca(2+) increased AG-b activity. However, Ag(+), Hg(2+), Fe(3+), EDTA and SDS inhibited AG-a and AG-b activities. The main hydrolysates of agarose by AG-a were neoagarotetraose and neoagarohexaose. The main hydrolysates of agarose by AG-b were neoagarooctaose and neoagarohexaose. When the mixture of AG-a and AG-b were used, agarose was mainly degraded into neoagarobiose.
authors.affiliation: Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China.
authors.forename: Wandong
authors.initials: W
authors.lastname: Fu
authors.forename: Baoqin
authors.initials: B
authors.lastname: Han
authors.forename: Delin
authors.initials: D
authors.lastname: Duan
authors.forename: Wanshun
authors.initials: W
authors.lastname: Liu
authors.forename: Changhong
authors.initials: C
authors.lastname: Wang
mesh_terms: D000645:Ammonium Sulfate; D001426:Bacterial Proteins / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism*; D002244:Carbon / Q000378:metabolism; D002413:Cations, Divalent / Q000494:pharmacology; D005591:Chemical Fractionation; D002681:China; D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D003470:Culture Media / Q000737:chemistry; D004492:Edetic Acid / Q000494:pharmacology; D004591:Electrophoresis, Polyacrylamide Gel; D020536:Enzyme Activators / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004795:Enzyme Stability; D005697:Galactosides / Q000378:metabolism; D006026:Glycoside Hydrolases / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D008670:Metals / Q000494:pharmacology; D008970:Molecular Weight; D009844:Oligosaccharides / Q000378:metabolism; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012623:Seawater / Q000382:microbiology*; D012685:Sepharose / Q000378:metabolism; D017422:Sequence Analysis, DNA; D012967:Sodium Dodecyl Sulfate / Q000494:pharmacology; D013696:Temperature; D014733:Vibrio / Q000145:classification / Q000201:enzymology* / Q000302:isolation & purification
chemical_list: D001426:Bacterial Proteins; D002413:Cations, Divalent; D003470:Culture Media; D020536:Enzyme Activators; D004791:Enzyme Inhibitors; D005697:Galactosides; D008670:Metals; D009844:Oligosaccharides; D012336:RNA, Ribosomal, 16S; C081798:neoagarotetraose; D012967:Sodium Dodecyl Sulfate; D002244:Carbon; D012685:Sepharose; D004492:Edetic Acid; D006026:Glycoside Hydrolases; C019624:agarase; D000645:Ammonium Sulfate