The leaves of Boscia senegalensis are traditionally used in West Africa in cereal protection against pathogens, pharmacologic applications, and food processing. Activities of a-amylase, b-amylase, exo-(1®3, 1®4)-b-Dglucanase, and endo-(1®3)-b-D-glucanase were detected in these leaves. The endo-(1®3)-b-D-glucanase (EC 188.8.131.52) was purified 203-fold with 57% yield. The purified enzyme is a nonglycosylated monomeric protein with a molecular mass of 36 kDa and pI ³ 10.3. Its optimal activity occurred at pH 4.5 and 50°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 matrixassisted 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)-b-glucan chains in an endo fashion. This property is unusual for endo-acting (1®3)-b-D-glucanase from plants. The involvement of the enzyme in plant defense against pathogenic microorganisms such as fungi is discussed.
- a-Amylase; b-amylase; b-glucanase; yeast glucan; high-performance liquid chromatography; MALDI-TOF-MS,
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