Purification and properties of β-mannosidase from malted barley

Clifford W. Houston, Steve B. Latimer, Earl D. Mitchell

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    13 Scopus citations


    β-Mannosidase (β-mannoside mannohydrolase, EC was extracted and purified about 100-fold from malted barley. The purified preparation was free of α-mannosidase, β-N-acetylhexosaminidase, α-galactosidase and β-glucosidase. The purified enzyme was active between pH 3 and 6 and exhibited a Km value of 3.2·10-4 M using the p-nitrophenyl-β-d-mannopyranoside as the substrate. 2-Amino-2-deoxy-d-mannose is a competitive inhibitor (K1 = 1.18·10-4 M), p-Nitrophenyl-α-d-mannopyranoside activated the enzyme at low concentration but competitively inhibits at higher concentrations. β-Mannosidase had maximum activity at 55 °C but this dropped significantly at 70 °C. Specific cleavage of β-mannoside linkages by the purified β-mannosidase was demonstrated using a β-(1-4)mannosylmannose as substrate. The enzyme showed the molecular weight is about 88 000 as determined by acrylamide gel electrophoresis.

    Original languageEnglish (US)
    Pages (from-to)276-282
    Number of pages7
    JournalBBA - Enzymology
    Issue number1
    StatePublished - Nov 25 1974

    ASJC Scopus subject areas

    • Medicine(all)


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