Purification and Characterization of α-D-Mannosidase from the Seeds of Kaya, Torreya nucifera

Abstract

Alpha-D-mannosidase was purified from the extract of seeds of Kaya, Torreya nucifera. The purified enzyme had a molecular mass of ∼3.6 x 10⁵ daltons. This enzyme had an optimum pH at 4.5, and was stable at pH between 5.5 and 6.5. This enzyme appeared to be a metal enzyme containing Zn²⁺. The enzyme hydrolyzed p-nitrophenyl-α-D-mannoside, methyl-α-D-mannoside, α-1→3-man-nobiose, and α-1→6-mannobiose, with K_m of 0.785 mM, 0.236 M, 2.505 mM, and 0.268 mM, fespectively. The hydrolysis of various α-linked mannobioses indicated that the enzyme hydrolyzes the α-mannobioses in the order of α-(1→2)> -(1→6)> -(1→3).