Characterization of a β-D-mannosidase from a marine gastropod, Aplysia kurodai

• Zahura, Umme Afsari

• Rahman, Mohammad Matiur

• Inoue, Akira

• Ojima, Takao

抄録

A β-D-mannosidase (EC 3.2.1.25) with a molecular mass of approximately 100 kDa was purified from the digestive fluid of a marine gastropod Aplysia kurodai by ammonium sulfate fractionation followed by column chromatographies on TOYOPEARL Butyl-650 M, TOYOPEARL DEAE-650 M, and Superdex 200 10/300 GL. This enzyme, named AkMnsd in the present study, showed optimal activities at pH 4.5 and 40℃ and was stable at the acidic pH range from 2.0 to 6.7 and the temperature below 38℃. The Km and Vmax values for AkMnsd determined at pH 6.0 and 30℃ with p-nitrophenyl β-D-mannopyranoside were 0.10 mM and 3.75 μmol/min/mg, respectively. AkMnsd degraded various polymer mannans as well as mannooligosaccharides liberating mannose as a major degradation product. Linear mannan from green alga Codium fragile was completely depolymerized by AkMnsd in the presence of AkMan, an endolytic β-mannanase, which we previously isolated from the same animal (Zahura et al., Comp. Biochem. Physiol. B 157, 137-148 (2010)). A cDNA encoding AkMnsd was amplified from the Aplysia hepatopancreas cDNA by the PCR using degenerated primers designed on the basis of N-terminal and internal amino-acid sequences of AkMnsd. The cloned AkMnsd cDNA consisted of 2985 bp and encoded an amino-acid sequence of 931 residues with the calculated molecular mass of 101970 Da. The deduced sequence of AkMnsd showed 20-43% amino-acid identity to those of glycoside-hydrolase-family 2 (GHF2) β-mannosidases. The catalytically important amino-acid residues determined in GHF2 enzymes were completely conserved in AkMnsd. Thus, AkMnsd is regarded as a new member of GHF2 mannosidase from marine gastropod.

収録刊行物

• Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology

  Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology 162 (1-3), 24-33, 2012-05

  Elsevier

キーワード

• β-mannosidase
• β-1,4-mannan

詳細情報

• CRID: 1050001339010775808
• NII論文ID: 120004146563
• HANDLE: 2115/49356
• ISSN: 10964959
• 本文言語コード: en
• 資料種別: journal article
• データソース種別:
  • IRDB
  • CiNii Articles