Exolytic hydrolysis of toxic plant glucosides by guinea pig liver cytosolic beta-glucosidase

We demonstrate that although the guinea pig liver cytosolic beta-glucosidase does not catalyze the hydrolysis of gentiobiose, it does hydrolyze, disaccharide-containing glycosides such as p-nitrophenyl-, beta-D-gentiobioside (Glc beta1 leads to 6 Glcbeta-pNP) and mandelonitrile-beta-D-gentiobioside...

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Bibliographic Details
Published in:The Journal of biological chemistry 1992-07, Vol.267 (20), p.14027-14032
Main Authors: Gopalan, V. (University of New Mexico, Albuquerque, NM), Pastuszyn, A, Galey, W.R. Jr, Glew, R.H
Format: Article
Language:English
Subjects:
AMIGDALINA
amygdalin
Amygdalin - metabolism
AMYGDALINE
Analytical, structural and metabolic biochemistry
Animals
beta -glucosidase
beta-Glucosidase - metabolism
Biological and medical sciences
Carbohydrate Sequence
Chromatography, High Pressure Liquid
CITOPLASMA
COBAYA
COBAYE
COMPOSE PHENOLIQUE
COMPUESTOS FENOLICOS
CYTOPLASME
Cytosol - enzymology
Disaccharides - metabolism
enzymatic activity
Enzymes and enzyme inhibitors
Fundamental and applied biological sciences. Psychology
GLICOSIDOS
GLUCOSIDASA
GLUCOSIDASE
glucosides
Glucosides - metabolism
GLYCOSIDE
Guinea Pigs
HIDROLISIS
Hydrolases
HYDROLYSE
hydrolysis
Kinetics
liver
Liver - enzymology
Molecular Sequence Data
Plants, Toxic
Substrate Specificity
TOXICIDAD
TOXICITE
transport
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Summary:We demonstrate that although the guinea pig liver cytosolic beta-glucosidase does not catalyze the hydrolysis of gentiobiose, it does hydrolyze, disaccharide-containing glycosides such as p-nitrophenyl-, beta-D-gentiobioside (Glc beta1 leads to 6 Glcbeta-pNP) and mandelonitrile-beta-D-gentiobioside (amygdalin). Furthermore, we establish that the enzyme attacks disaccharide glycosides exolytically; specifically, we document the exolytic deglucosylation of amygdalin and the generation of the intermediate monosaccharide glycoside mandelonitrile-beta-D-glucoside prior to the formation of the aglycone (mandelonitrile). We also show that the cytosolic beta-glucosidase catalyzes the hydrolysis of various phenolic (e.g. arbutin and salicin) and cyanogenic plant glucosides (e.g. prunasin). Using the everted gut-sack technique, we demonstrate that the plant glucosides, amygdalin, prunasin, and vicine, are transported across the small intestine of the guinea pig efficiently and without being hydrolyzed. Based on thess data we speculate that the cytosolic beta-glucosidase may participate in biotransformation of toxic plant glucosides
ISSN:0021-9258
1083-351X
DOI:10.1016/s0021-9258(19)49673-7