beta-Glucosidase catalyzing specific hydrolysis of an iridoid beta-glucoside from Plumeria obtusa.
Acta Biochim Biophys Sin (Shanghai)
; 38(8): 563-70, 2006 Aug.
Article
en En
| MEDLINE
| ID: mdl-16894479
ABSTRACT
An iridoid beta-glucoside, namely plumieride coumarate glucoside, was isolated from the Plumeria obtusa (white frangipani) flower. A beta-glucosidase, purified to homogeneity from P. obtusa, could hydrolyze plumieride coumarate glucoside to its corresponding 13-O-coumarylplumieride. Plumeria beta-glucosidase is a monomeric glycoprotein with a molecular weight of 60.6 kDa and an isoelectric point of 4.90. The purified beta-glucosidase had an optimum pH of 5.5 for p-nitrophenol (pNP)-beta-D-glucoside and for its natural substrate. The Km values for pNP-beta-D-glucoside and Plumeria beta-glucoside were 5.04+/-0.36 mM and 1.02+/-0.06 mM, respectively. The enzyme had higher hydrolytic activity towards pNP-beta-D-fucoside than pNP-beta-D-glucoside. No activity was found for other pNP-glycosides. Interestingly, the enzyme showed a high specificity for the glucosyl group attached to the C-7' position of the coumaryl moiety of plumieride coumarate glucoside. The enzyme showed poor hydrolysis of 4-methylumbelliferyl-beta-glucoside and esculin, and did not hydrolyze alkyl-beta-glucosides, glucobioses, cyanogenic-beta-glucosides, steroid beta-glucosides, nor other iridoid beta-glucosides. In conclusion, the Plumeria beta-glucosidase shows high specificity for its natural substrate, plumieride coumarate glucoside.
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Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Ácidos Cumáricos
/
Apocynaceae
/
Iridoides
/
Celulasas
Idioma:
En
Revista:
Acta Biochim Biophys Sin (Shanghai)
Asunto de la revista:
BIOFISICA
/
BIOQUIMICA
Año:
2006
Tipo del documento:
Article
País de afiliación:
Tailandia