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)

(R)- and (S)-2-Azido-1-methoxyethyl beta-D-glucopyranosides (16) and (17), (R)- and (S)-3-azido-1-methoxypropyl beta-D-glucopyranosides (18) and (19), (R,S)-4-azido-1-methoxybutyl beta-D-glucopyranoside (20), and (R,S)-5-azido-1-methoxypentyl beta-D-glucopyranoside (22) were synthesized from omega-substituted dimethyl acetals of acetaldehyde, propanal, butanal, and pentanal by trimethylsilyl triflate-catalysed transacetalation using 1-O-trimethysilyl 2,3,4,6-tetra-O-acetyl-beta-D-glucose (1) as acceptor. Most of the acetylated (R,S)-epimers could be resolved into pure compounds by column chromatography. Preliminary tests showed that the deacetylated acetal glucosides carrying omega-bromo, azido, or acetamido substituents in the aglycon are good substrates for beta-D-glucosidase from sweet almonds. The corresponding omega-amino derivatives of compounds 16, 19, 20, and 22, (R)-2-amino-1-methoxyethyl beta-D-glucopyranoside (23), (S)-3-amino-1-methoxypropyl beta-D-glucopyranoside (24), (R,S)-4-amino-1-methoxybutyl beta-D-glucopyranoside (25), and (R,S)-5-amino-1-methoxypentyl beta-D-glucopyranoside (26) proved almost completely resistant to beta-D-glucosidase. The stability of the glucosides against enzyme hydrolysis is dependent on the distance between the amino group and the anomeric center.
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PMID:Syntheses of homologous omega-aminated 1-methoxyalkyl beta-D-glucopyranosides as potential beta-D-glucosidase inhibitors. 312 57

Barley (Hordeum vulgare) seedlings contain five cyano glucosides derived from the amino acid L-leucine (Leu). The chemical structure and the relative abundance of the cyano glucosides were investigated by liquid chromatography-mass spectrometry and nuclear magnetic resonance analyses using spring barley cultivars with high, medium, and low cyanide potential. The barley cultivars showed a 10-fold difference in their cyano glucoside content, but the relative content of the individual cyano glucosides remained constant. Epiheterodendrin, the only cyanogenic glucoside present, comprised 12% to 18% of the total content of cyano glucosides. It is proposed that the aglycones of all five cyano glucosides are formed by the initial action of a cytochrome P450 enzyme of the CYP79 family converting L-Leu into Z-3-methylbutanal oxime and subsequent action of a less specific CYP71E enzyme converting the oxime into 3-methylbutyro nitrile and mediating subsequent hydroxylations at the alpha-, as well as beta- and gamma-, carbon atoms. Presence of cyano glucosides in the barley seedlings was restricted to leaf tissue, with 99% confined to the epidermis cell layers of the leaf blade. Microsomal preparations from epidermal cells were not able to convert L-[(14)C]Leu into the biosynthetic intermediate, Z-3-methylbutanal-oxime. This was only achieved using microsomal preparations from other cell types in the basal leaf segment, demonstrating translocation of the cyano glucosides to the epidermal cell layers after biosynthesis. A beta-glucosidase able to degrade epiheterodendrin was detected exclusively in yet a third compartment, the endosperm of the germinating seed. Therefore, in barley, a putative function of cyano glucosides in plant defense is not linked to cyanide release.
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PMID:Leucine-derived cyano glucosides in barley. 1211 61