Effects of size of carbohydrate chain on protease digestion of Aspergillus niger endo-beta-1,4-glucanase.
Three different carbohydrate-depleted enzymes were prepared from an endo-beta-1,4-glucanase of Aspergillus niger IFO31125 by treatment with endo-beta-N-acetylglucosaminidase or alpha-mannosidase. They were purified by Concanavalin A-Sepharose affinity and DEAE ion-exchange column chromatographies. The molecular sizes of these enzymes had been decreased from 40 kDa containing 9.0% carbohydrate to 39, 38, and 37 kDa with carbohydrate at 4.5, 1.3, and 0.8% (wt/wt), respectively. The native and these carbohydrate-depleted enzymes were compared in their enzymatic properties, and it was found that they were identical in their catalytic activities and both thermal and pH stabilities. However, the 37-kDa enzyme was more susceptible to proteolysis by Savinase, proteinase K, and Pronase E. On the other hand, the specific protease trypsin showed no such effect on activity of all enzymes. These results suggested that the core structure of the asparagine-linked sugar chain, which consisted of three monosaccharide residues, contributed to the high stability of the endo-beta-1,4-glucanase against protease digestion.
Akiba
S
S
Biological Science Laboratories, Kao Corporation, Ibaraki, Japan.
Yamamoto
K
K
Kumagai
H
H
D001234:Aspergillus niger / Q000201:enzymology*; D002240:Carbohydrate Sequence; D002241:Carbohydrates / Q000737:chemistry*; D002480:Cellulase / Q000737:chemistry / Q000378:metabolism*; D010450:Endopeptidases / Q000378:metabolism*; D004795:Enzyme Stability; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D008969:Molecular Sequence Data; D008970:Molecular Weight; D013696:Temperature
D002241:Carbohydrates; D002480:Cellulase; D010450:Endopeptidases