Purification and characterization of a beta-glucosidase from rye (Secale cereale L.) seedlings

Citation
M. Sue et al., Purification and characterization of a beta-glucosidase from rye (Secale cereale L.) seedlings, PLANT SCI, 155(1), 2000, pp. 67-74
Citations number
22
Categorie Soggetti
Plant Sciences","Animal & Plant Sciences
Journal title
PLANT SCIENCE
ISSN journal
01689452 → ACNP
Volume
155
Issue
1
Year of publication
2000
Pages
67 - 74
Database
ISI
SICI code
0168-9452(20000612)155:1<67:PACOAB>2.0.ZU;2-G
Abstract
Cyclic hydroxamic acids and a glucosidase that occur in I ye seedlings were investigated. The concentration of the glucoside of 2.3-dihydroxy-1,4-benz oxazin-3-one (DIBOA-Glc) in shoots increased soon after germination and dec reased to a lower, constant level as the plants started autotrophic growth. Cyclic hydroxamic acid glucoside beta-glucosidase activity also occurred t ransiently, and the timing of the increase and decrease was concurrent with that of cyclic hydroxamic acid glucosides. The glucosidase was isolated fr om 48-h-old rye shoots and purified to apparent homogeneity by using isoele ctric precipitation, anion exchange chromatography, and gel filtration. The isoelectric point and the optimum reaction temperature were 4.9-5.1 and 25 -30 degrees C, respectively. The N-terminal amino acid sequence was almost identical to that of the wheat glucosidases, but did not show any similarit y to the sequences of other glucosidases of plant origin. SDS- and native-P AGE analyses showed that rye had several isozymes of glucosidase, and each isozyme was an oligomer of 60-kDa monomers with a molecular mass of similar to 300 kDa. The enzyme was highly active not only for DIMBOA-Glc but also for its 7-demethoxy analogue. DIBOA-Glc, which was different from the speci ficities of maize and wheat glucosidases. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.