Transglycosylating and hydrolytic activities of the beta-mannosidase from Trichoderma reesei.
A purified beta-mannosidase (EC 3.2.1.25) from the fungus Trichoderma reesei has been identified as a member of glycoside hydrolase family 2 through mass spectrometry analysis of tryptic peptides. In addition to hydrolysis, the enzyme catalyzes substrate transglycosylation with p-nitrophenyl beta-mannopyranoside. Structures of the major and minor products of this reaction were identified by NMR analysis as p-nitrophenyl mannobiosides and p-nitrophenyl mannotriosides containing beta-(1-->4) and beta-(1-->3) linkages. The rate of donor substrate hydrolysis increased in presence of acetonitrile and dimethylformamide, while transglycosylation was weakly suppressed by these organic solvents. Differential ultraviolet spectra of the protein indicate that a rearrangement of the hydrophobic environment of the active site following the addition of the organic solvents may be responsible for this hydrolytic activation.
Eneyskaya
Elena V
EV
Petersburg Nuclear Physics Institute, Russian Academy of Science, Molecular and Radiation Biophysics Division, Gatchina, Leningrad District, Russia.
Sundqvist
Gustav
G
Golubev
Alexander M
AM
Ibatullin
Farid M
FM
Ivanen
Dina R
DR
Shabalin
Konstantin A
KA
Brumer
Harry
H
Kulminskaya
Anna A
AA