Polysaccharide hydrolases from leaves of Boscia senegalensis: properties of endo-(1-->3)-beta-D-glucanase.
Appl Biochem Biotechnol
; 94(3): 225-41, 2001 Jun.
Article
em En
| MEDLINE
| ID: mdl-11563825
ABSTRACT
The leaves of Boscia senegalensis are traditionally used in West Africa in cereal protection against pathogens, pharmacologic applications, and food processing. Activities of alpha-amylase, beta-amylase, exo-(1-->3, 1-->4)-beta-D-glucanase, and endo-(1-->3)-beta-D-glucanase were detected in these leaves. The endo-(1-->3)-beta-D-glucanase (EC 3.2.1.39) was purified 203-fold with 57% yield. The purified enzyme is a nonglycosylated monomeric protein with a molecular mass of 36 kDa and pI > or = 10.3. Its optimal activity occurred at pH 4.5 and 50 degrees C. Kinetic analysis gave Vmax, kcat, and Km values of 659 U/mg, 395 s(-1), and 0.42 mg/mL, respectively, for laminarin as substrate. The use of matrix-assisted laser desorption ionization time-of-flight mass spectrometry and high-performance liquid chromatography revealed that the enzyme hydrolyzes not only soluble but also insoluble (1-->3)-beta-glucan chains in an endo fashion. This property is unusual for endo-acting (1-->3)-beta-D-glucanase from plants. The involvement of the enzyme in plant defense against pathogenic microorganisms such as fungi is discussed.
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Base de dados:
MEDLINE
Assunto principal:
Plantas Comestíveis
/
Folhas de Planta
/
Glucana Endo-1,3-beta-D-Glucosidase
País como assunto:
Africa
Idioma:
En
Ano de publicação:
2001
Tipo de documento:
Article