The effects of beta-mercaptoethanol and sodium dodecyl sulfate on the Humicola insolens beta-glucosidase.
Hydrolysis of p-nitrophenyl-beta-D-glucoside by the beta-glucosidase of a thermophilic and cellulolytic fungus, Humicola insolens was stimulated by two-fold in the presence of high concentrations of beta-mercaptoethanol. This enzyme did not have any free sulfhydryl groups and high concentrations of beta-mercaptoethanol (5% v/v) reduced all of the three disulfide bonds present in the enzyme. In contrast, the hydrolysis of cellobiose and cellulose polymers was inhibited by 50% under the same conditions. Sodium dodecyl sulfate (1% w/v) even in combination with beta-mercaptoethanol did not show any significant effects on this enzyme. These unusual properties suggest that this enzyme may be of significant importance for understanding the structure of the enzyme.
Rao
U S
US
Department of Biochemistry, Indian Institute of Science, Bangalore.
Murthy
S K
SK
D002475:Cellobiose / Q000378:metabolism; D002482:Cellulose / Q000378:metabolism; D002850:Chromatography, Gel; D003545:Cysteine / Q000032:analysis; D004220:Disulfides / Q000737:chemistry; D005656:Fungal Proteins / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism; D005960:Glucosides / Q000378:metabolism; D008623:Mercaptoethanol / Q000494:pharmacology*; D008745:Methylation; D003904:Mitosporic Fungi / Q000201:enzymology*; D012967:Sodium Dodecyl Sulfate / Q000494:pharmacology*; D014508:Urea; D001617:beta-Glucosidase / Q000378:metabolism*
D004220:Disulfides; D005656:Fungal Proteins; D005960:Glucosides; D002475:Cellobiose; C025193:4-nitrophenyl beta-D-glucoside; D012967:Sodium Dodecyl Sulfate; D008623:Mercaptoethanol; D014508:Urea; D002482:Cellulose; D001617:beta-Glucosidase; D005947:Glucose; D003545:Cysteine