title: Isolation and characterization of two forms of beta-D-glucosidase from Aspergillus niger.
abstract: beta-D-glucosidase purified from commercial preparations of clarified culture broth of Aspergillus niger (Novo SP188) was shown to elute as two distinct species during analytical anion-exchange chromatography (AEC). However, the two enzyme forms behaved identically on sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis (PAGE), high-performance size-exclusion chromatography (HPSEC), and isoelectric focusing. Also, the N-terminal amino acid sequence, amino acid composition, fingerprint of tryptic-digest peptides, circular dichroism spectra, and reaction kinetics appear identical for these forms. This feature of the A. niger enzyme is distinctly different from beta-D-glucosidase isozymes reported from other sources, where multiple forms tend to differ in molecular weight and/or isoelectric pH. Michaelis-Menten kinetic analysis also gave comparable results for the two forms. The distinct behavior on AEC was explained by considering the differences in N-linked carbohydrates liberated from both species following treatment with endoglycosidase H or F.
authors.affiliation: Applied Biological Sciences Branch, National Renewable Energy Laboratory, Golden, CO 80401.
authors.forename: M E
authors.initials: ME
authors.lastname: Himmel
authors.forename: W S
authors.initials: WS
authors.lastname: Adney
authors.forename: J W
authors.initials: JW
authors.lastname: Fox
authors.forename: D J
authors.initials: DJ
authors.lastname: Mitchell
authors.forename: J O
authors.initials: JO
authors.lastname: Baker
mesh_terms: D000595:Amino Acid Sequence; D001234:Aspergillus niger / Q000201:enzymology*; D002152:Calorimetry, Differential Scanning; D002852:Chromatography, Ion Exchange; D002942:Circular Dichroism; D004591:Electrophoresis, Polyacrylamide Gel; D006031:Glycosylation; D007525:Isoelectric Focusing; D007527:Isoenzymes / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D007700:Kinetics; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000032:analysis; D010455:Peptides / Q000032:analysis; D001617:beta-Glucosidase / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism
chemical_list: D007527:Isoenzymes; D009844:Oligosaccharides; D010455:Peptides; D001617:beta-Glucosidase