Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.21 (beta-glucosidase)
 3,280 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Chromatographic examination has shown that the enzymic hydrolysis of amygdalin by an almond beta-glucosidase preparation proceeds consecutively: amygdalin was hydrolysed to prunasin and glucose; prunasin to mandelonitrile and glucose; mandelonitrile to benzaldehyde and hydrocyanic acid. Gentiobiose was not formed during the enzymic hydrolysis. The kinetics of the production of mandelonitrile and hydrocyanic acid from amygdalin by the action of the beta-glucosidase preparation favour the probability that three different enzymes are involved, each specific for one hydrolytic stage, namely, amygdalin lyase, prunasin lyase and hydroxynitrile lyase. Cellulose acetate electrophoresis of the enzyme preparation showed that it contained a number of enzymically active components.
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PMID:The enzymic hydrolysis of amygdalin. 429 88

Almonds are a rich source of mandelonitrile lyase (oxynitrilase) and beta-glucosidase. The isolation of these two enzymes from sweet almonds requires fractional ammonium sulfate precipitation followed by ion-exchange chromatography on diethylaminoethyl-(DEAE) and carboxymethylcellulose (CMC) columns. In the present investigation different electrophoretic techniques such as sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), isoelectric focusing in immobilized pH gradients (IEF-IPG), and capillary electrophoresis were used to characterize these two enzymes. For the first time, beta-glucosidase and oxynitrilase were separated in an immobilized pH gradient of one pH unit. Capillary zone electrophoresis (CZE) was an excellent tool for analysis of the purity of enzyme preparations, achieving complete separation of various protein constituents in only 15 min. CZE showed a resolving capacity for the separation of enzyme forms comparable to that of isoelectric focusing in an immobilized pH gradient.
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PMID:Analysis of mandelonitrile lyase and beta-glucosidase from sweet almonds by combined electrophoretic techniques. 942 Jan 68

In macerates of black cherry (Prunus serotina Ehrh.) leaves and stems, (R)-prunasin is catabolized to HCN, benzaldehyde, and D-glucose by the sequential action of prunasin hydrolase (EC 3.2.1.21) and (R)-(+)-mandelonitrile lyase (EC 4.1.2.10). Immuno-cytochemical techniques have shown that within these organs prunasin hydrolase occurs within the vacuoles of phloem parenchyma cells. In arborescent leaves, mandelonitrile lyase was also located in phloem parenchyma vacuoles, but comparison of serial sections revealed that these two degradative enzymes are usually localized within different cells.
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PMID:Immunocytochemical Localization of Prunasin Hydrolase and Mandelonitrile Lyase in Stems and Leaves of Prunus serotina. 1223 9

The tissue distributions of dhurrin [p-hydroxy-(S)-mandelonitrile-beta-d-glucoside] and of enzymes involved in its metabolism have been investigated in leaf blades of light-grown Sorghum bicolor seedlings. Enzymic digestion of these leaves using cellulase has enabled preparations of epidermal and mesophyll protoplasts and bundle sheath strands to be isolated with only minor cross-contamination. Dhurrin was located entirely in the epidermal layers of the leaf blade, whereas the two enzymes responsible for its catabolism, namely dhurrin beta-glucosidase and hydroxynitrile lyase, resided almost exclusively in the mesophyll tissue. The final enzyme of dhurrin biosynthesis, uridine diphosphate glucose:p-hydroxymandelonitrile glucosyltransferase, was found in both mesophyll (32% of the total activity of the leaf blade) and epidermal (68%) tissues. The bundle sheath strands did not contain significant amounts of dhurrin or of these enzymes. It was concluded that the separation of dhurrin and its catabolic enzymes in different tissues prevents its large scale hydrolysis under normal physiological conditions. The well documented production of HCN (cyanogenesis), which occurs rapidly on crushing Sorghum leaves, would be expected to proceed when the contents of the ruptured epidermal and mesophyll cells are allowed to mix.
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PMID:Tissue Distributions of Dhurrin and of Enzymes Involved in Its Metabolism in Leaves of Sorghum bicolor. 1666 Aug 50

Studies with purified mesophyll and epidermal protoplasts and bundle sheath strands have shown that the cyanogenic glucoside dhurrin (p-hydroxy-(S)-mandelonitrile-beta-d-glucoside) is localized in the epidermis of sorghum leaves whereas the enzymes involved in its degradation (dhurrin beta-glucosidase and hydroxynitrile lyase) are localized in the mesophyll tissue (Kojima M, JE Poulton, SS Thayer, EE Conn 1979 Plant Physiol 63: 1022-1028). The subcellular localization of these enzymes has now been examined using linear 30 to 55% (w/w) sucrose gradients by fractionation of mesophyll protoplast components. The hydroxynitrile lyase is found in the supernatant fractions suggesting a cytoplasmic (soluble cytoplasm, microsomal or vacuolar location). The dhurrin beta-glucosidase (dhurrinase) is particulate and mostly chloroplast-associated. The dhurrinase activity peak has a shoulder of activity more dense than that of the intact chloroplasts. This shoulder does not coincide with markers of any other cell fraction.In studies of chloroplasts isolated from ruptured mesophyll protoplasts by differential, low-speed centrifugation, the dhurrinase partitions in the same manner as the chloroplast marker triose phosphate dehydrogenase. Chloroplast localization of the beta-glucosidase has also been shown in histochemical studies using 6-bromo-2-naphthyl-beta-d-glucoside substrate coupled with fast Blue B.
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PMID:Subcellular Localization of Dhurrin beta-Glucosidase and Hydroxynitrile Lyase in the Mesophyll Cells of Sorghum Leaf Blades. 1666 25