Publications

• Vicianin hydrolase is a novel cyanogenic beta-glycosidase specific to beta-vicianoside (6-O-alpha-L-arabinopyranosyl-beta-D-glucopyranoside) in seeds of Vicia angustifolia.

  Ahn Y.O., Saino H., Mizutani M., Shimizu B., Sakata K.

  The cyanogenic disaccharide glycoside, vicianin [mandelonitrile beta-vicianoside (6-O-alpha-L-arabinopyranosyl-beta-D-glucopyranoside)], is accumulated in seeds of Vicia angustifolia var. segetalis. Vicianin hydrolase (VH) catalyzes the hydrolysis of vicianin into mandelonitrile and a disaccharide ... >> More

  The cyanogenic disaccharide glycoside, vicianin [mandelonitrile beta-vicianoside (6-O-alpha-L-arabinopyranosyl-beta-D-glucopyranoside)], is accumulated in seeds of Vicia angustifolia var. segetalis. Vicianin hydrolase (VH) catalyzes the hydrolysis of vicianin into mandelonitrile and a disaccharide vicianose. VH was purified from the seeds using DEAE-, CM- and Con A-Sepharose chromatography, and the molecular mass of the purified VH was estimated to be 56 kDa on SDS-PAGE. The N-terminal amino acid sequence of the purified VH was determined, and a cDNA encoding VH was obtained. The deduced VH protein consists of a 509 amino acid polypeptide containing a putative secretion signal peptide. It shares about 50% identity with various kinds of plant beta-glycosidases including tea leaf beta-primeverosidase and furcatin hydrolase, and is classified in family 1 of the glycosyl hydrolases. The VH transcript was detected abundantly in seeds and moderately in flowers, but only slightly in leaves, stems and roots, indicating that the organ distribution of VH expression is similar to that of the substrate vicianin. The recombinant VH was produced in insect cells with a baculovirus system, and was compared with the native VH in terms of substrate specificity. Both enzymes hydrolyzed vicianin to release vicianose, demonstrating that VH is a disaccharide-specific beta-glycosidase. VH also hydrolyzed the mandelonitrile beta-glucoside prunasin to some extent but did not hydrolyze the gentiobioside amygdalin, both of which contain the same aglycone as vicianin. Thus, VH is a unique cyanogenic glycosidase showing high glycone specificity for the disaccharide vicianoside. << Less

  Plant Cell Physiol. 48:938-947(2007) [PubMed] [EuropePMC]

• Catabolism of Cyanogenic Glycosides by Purified Vicianin Hydrolase from Squirrel's Foot Fern (Davallia Trichomanoides Blume).

  Lizotte P.A., Poulton J.E.

  Vicianin hydrolase, which catalyzes the hydrolysis of vicianin (K(m), 4.9 millimolar) to (R)-mandelonitrile and vicianose at an optimum pH of 5.5, was extensively purified from the young fronds and fiddleheads of the squirrel's foot fern (Davallia trichomanoides Blume) using DEAE-cellulose and Ult ... >> More

  Vicianin hydrolase, which catalyzes the hydrolysis of vicianin (K(m), 4.9 millimolar) to (R)-mandelonitrile and vicianose at an optimum pH of 5.5, was extensively purified from the young fronds and fiddleheads of the squirrel's foot fern (Davallia trichomanoides Blume) using DEAE-cellulose and Ultrogel HA chromatography. The native molecular weight of the enzyme was 340,000, and the isoelectric point was 4.6 to 4.7. SDS-PAGE analysis yielded three polypeptides with molecular weights of 56,000, 49,000, and 32,500. The enzyme hydrolyzed only a narrow range of glycosides and, among cyanogenic glycosides, exhibited a strict requirement for (R)-epimers and a preference for disaccharides over monosaccharides. (R)-Amygdalin, (R)-prunasin and p-nitrophenyl-beta-d-glucoside were hydrolyzed at 27, 14, and 3%, respectively, of the rate of vicianin hydrolysis. Mixed substrate studies showed that (R)-vicianin, (R)-prunasin, and p-nitrophenyl-beta-d-glucoside competed for the same active site. The enzyme was significantly inhibited by castanospermine, delta-gluconolactone, and p-chloromercuriphenylsulfonate. Failure to recognize concanavalin A-Sepharose 4B and to stain with periodic acid-Schiff reagent indicated that the enzyme was not a glycoprotein. << Less

  Plant Physiol 86:322-324(1988) [PubMed] [EuropePMC]