Beta-glucosidase multiplicity from Aspergillus tubingensis CBS 643.92: purification and characterization of four beta-glucosidases and their differentiation with respect to substrate specificity, glucose inhibition and acid tolerance.
From Aspergillus tubingensis CBS 643.92 four distinct beta-glucosidases (I-IV) were purified by a four-step purification procedure. SDS-PAGE revealed molecular masses of 131, 126, 54 and 54 kDa, respectively, and their isoelectric points were determined to be 4.2, 3.9, 3.7 and 3.6, respectively. The beta-glucosidases exhibited high diversity with respect to pH and temperature optima and stability, as well as to substrate specificity and glucose tolerance. The major beta-glucosidase (I) preferentially hydrolysed oligosaccharides. The acid-stable and heat-tolerant beta-glucosidase II hydrolysed aryl and terpenyl beta-D-glucosides as well as 1-O-trans-cinnamoyl beta-D-glucoside. In contrast to beta-glucosidases I and II, the minor beta-glucosidases III and IV were found to be glucose-tolerant; inhibition constants of 470 and 600 mM, respectively, were determined.
Decker
C H
CH
Lehrstuhl für Lebensmittelchemie, Universität Würzburg, Germany.
Visser
J
J
Schreier
P
P
D000595:Amino Acid Sequence; D001230:Aspergillus / Q000201:enzymology*; D004591:Electrophoresis, Polyacrylamide Gel; D004795:Enzyme Stability; D005947:Glucose / Q000494:pharmacology*; D005960:Glucosides / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007526:Isoelectric Point; D007700:Kinetics; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009844:Oligosaccharides / Q000378:metabolism; D013379:Substrate Specificity; D013696:Temperature; D001617:beta-Glucosidase / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism*
D005960:Glucosides; D009844:Oligosaccharides; D001617:beta-Glucosidase; D005947:Glucose