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.

Nyckelord

beta-Mannosidase

Transglycosylation

p-Nitrophenyl

beta-mannooligosaccharides

Organic solvents

rhodotorula-glutinis

enzymatic-synthesis

organic-solvents

identification

trisaccharide

purification

glucanase

alignment

complex

system

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ref (ämneskategori)

art (ämneskategori)