Abstract
beta-N-Acetylhexosaminidase was produced by Trichoderma harzianum cultivated with chitin as the growth substrate. The enzyme was purified 13.2-fold to homogeneity by ultrafiltration and sequential chromatography on SP-Toyopearl and Sephacryl S-200. The molecular weight of the enzyme was estimated to be about 150,000 by gel filtration. The pH and temperature optima were 4.0-5.5 and 50 degrees C, respectively. The enzyme hydrolyzed N-acetylchitooligosaccharides at the non-reducing ends to release GlcNAc monomer. The enzyme showed a strict substrate specificity to the sugar chains in complex carbohydrates, hydrolyzing only the linkage of GlcNAc beta 1-3Gal, but not hydrolyzing the other linkages such as GalNAc beta 1-3Gal and GlcNAc beta 1-2Man.
MeSH terms
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Acetylgalactosamine / analogs & derivatives
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Acetylgalactosamine / metabolism
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Acetylglucosamine / analogs & derivatives
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Acetylglucosamine / metabolism
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Carbohydrate Sequence
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Enzyme Stability
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Fluorescent Dyes
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Fungal Proteins / drug effects
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Fungal Proteins / isolation & purification*
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Fungal Proteins / metabolism
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Hydrogen-Ion Concentration
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Kinetics
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Molecular Sequence Data
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Molecular Weight
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Oligosaccharides / metabolism
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Substrate Specificity
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Temperature
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Trichoderma / enzymology*
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beta-N-Acetylhexosaminidases / drug effects
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beta-N-Acetylhexosaminidases / isolation & purification*
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beta-N-Acetylhexosaminidases / metabolism
Substances
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Fluorescent Dyes
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Fungal Proteins
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Oligosaccharides
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4-nitrophenyl-2-acetamido-2-deoxygalactopyranoside
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4-nitrophenyl-N-acetyl-2-deoxyglucopyranoside
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beta-N-Acetylhexosaminidases
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Acetylgalactosamine
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Acetylglucosamine