Identification, characterization, and partial purification of glucoamylase from Aspergillus niger (syn A. ficuum) NRRL 3135.
The crude extracellular extract of Aspergillus niger (syn A. ficuum) NRRL 3135 contains glucoamylase (exo-1,4-alpha-D-glucanohydrolase, EC 3.2.1.2). The enzyme, a glycoprotein, was purified 7-fold by ion-exchange chromatography, chromatofocusing, and conconavalin A affinity chromatography. The molecular weight of the enzyme was estimated to be 90 kDa by SDS-PAGE and gel permeation chromatography. The pI of the enzyme was 3.4. The temperature optimum of the enzyme was 60 degrees C and the pH optimum was 5.0. The Vmax values for soluble starch, maltose, maltotriose, maltotretraose, maltopentaose, and isomaltose were 55.2, 11.7, 32.3, 47.8, 59.2, 12.5 nKat glucose/sec, respectively and the Km values for the same substrates were 0.09%, 0.67 mM, 0.76 mM, 0.76 mM, 0.68 mM, and 122.01 mM, respectively.
Vandersall
A S
AS
Department of Molecular Biology and Microbiology, University of Central Florida, Orlando 32816, USA.
Cameron
R G
RG
Nairn
C J
CJ
Yelenosky
G
G
Wodzinski
R J
RJ
D001234:Aspergillus niger / Q000201:enzymology*; D002846:Chromatography, Affinity; D002852:Chromatography, Ion Exchange; D004591:Electrophoresis, Polyacrylamide Gel; D004795:Enzyme Stability; D005087:Glucan 1,4-alpha-Glucosidase / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D006031:Glycosylation; D006863:Hydrogen-Ion Concentration; D007526:Isoelectric Point; D007700:Kinetics; D008970:Molecular Weight; D013213:Starch / Q000378:metabolism; D013379:Substrate Specificity; D013696:Temperature
D013213:Starch; D005087:Glucan 1,4-alpha-Glucosidase