title: Purification, characterization and end product analysis of dextran degrading endodextranase from Bacillus licheniformis KIBGE-IB25.
abstract: Degradation of high molecular weight dextran for obtaining low molecular weight dextran is based on the hydrolysis using chemical and enzymatic methods. Current research study focused on production, purification and characterization of dextranase from a newly isolated strain of Bacillus licheniformis KIBGE-IB25. Dextranase was purified up to 36 folds with specific activity of 1405 U/mg and molecular weight of 158 kDa. It was found that enzyme performs optimum cleavage of dextran (5000 Da, 0.5%) at 35 °C in 15 min at pH 4.5 with a Km and Vmax of 0.374 mg/ml and 182 μmol/min, respectively. Relative amino acid composition analysis of purified enzyme suggested the presence of higher number of hydrophobic, acidic and glycosylation promoting amino acids. The N-terminal sequence of dextranase KIBGE-IB25 was AYTVTLYLQG. It exhibited distinct amino acid sequence yet shared some inherent characteristics with glycosyl hydrolases (GH) family 49 and also testified the presence of O-glycosylation at N-terminal end.
authors.affiliation: The Karachi Institute of Biotechnology & Genetic Engineering (KIBGE), University of Karachi, Karachi 75270, Pakistan.
authors.forename: Rashida Rahmat
authors.initials: RR
authors.lastname: Zohra
authors.affiliation: The Karachi Institute of Biotechnology & Genetic Engineering (KIBGE), University of Karachi, Karachi 75270, Pakistan.
authors.forename: Afsheen
authors.initials: A
authors.lastname: Aman
authors.affiliation: The Karachi Institute of Biotechnology & Genetic Engineering (KIBGE), University of Karachi, Karachi 75270, Pakistan.
authors.forename: Asma
authors.initials: A
authors.lastname: Ansari
authors.affiliation: Food & Marine Resource Research Centre, Pakistan Council of Scientific & Industrial Research (PCSIR) Laboratories Complex, Karachi 75280, Pakistan.
authors.forename: Muhammad Samee
authors.initials: MS
authors.lastname: Haider
authors.affiliation: The Karachi Institute of Biotechnology & Genetic Engineering (KIBGE), University of Karachi, Karachi 75270, Pakistan. Electronic address: ali_kibge@yahoo.com.
authors.forename: Shah Ali Ul
authors.initials: SA
authors.lastname: Qader
mesh_terms: D000595:Amino Acid Sequence; D001407:Bacillus / Q000145:classification / Q000201:enzymology* / Q000235:genetics; D002021:Buffers; D002384:Catalysis; D003910:Dextranase / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism*; D003911:Dextrans / Q000378:metabolism*; D004789:Enzyme Activation; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D008970:Molecular Weight; D009994:Osmolar Concentration; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D013379:Substrate Specificity; D013696:Temperature
chemical_list: D002021:Buffers; D003911:Dextrans; D012336:RNA, Ribosomal, 16S; D003910:Dextranase
keywords: 6-alpha-d-glucan 6-glucanohydrolase; Bacillus licheniformis; Dextranase; Enzyme kinetics; Enzyme purification