Amino acid sequence at the active site of β-glucosidase a from bitter almonds

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Abstract

β-Glucosidase A from bitter almonds was inhibited by the substrate analogue 6-bromo-3,4,5-trihydroxycyclo[2-3H]hex-1-ene oxide. Incorporation of 2 mol inhibitor/mol of dimeric enzyme resulted in total loss of activity. From tryptic digests of the labeled enzyme two radioactive peptides were isolated and their sequence determined (binding site of inhibitor underlined): peptide I, containing approx. 60% of the label: Ile-Thr-Glx-Glx-Gly-Val-PheGly-Asp-Ser-Glx-(Ala, Asx2, Pro)-Lys and peptide II with approx. 30% of the label: Gly-Thr-Glx-Asp.

The specificity of the reaction of β-glucosidases (β-d-glucoside glucohydrolase, EC 3.2.1.21) with substrate-related epoxides indicates that the aspartic acid labeled in peptide I participates in the catalytic process of β-glucoside hydrolysis. The labeling of a second site is interpreted in terms of two, mutually exclusive, binding modes of the inhibitor.

References (15)

  • K. Weber et al.

    J. Biol. Chem.

    (1969)
  • K.R. Woods et al.

    Biochim. Biophys. Acta

    (1967)
  • A. Quaroni et al.

    J. Biol. Chem.

    (1976)
  • R.L. Heinrikson et al.

    J. Biol. Chem.

    (1965)
  • G. Legler et al.

    Z. Physiol. Chem.

    (1970)
  • B.S. Hartley

    Biochem. J.

    (1960)
  • K.J. Laidler et al.

    The Chemical Kinetics of Enzyme Action

There are more references available in the full text version of this article.

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