Purification, Characterization and Chemical Modification of the Xylanase from Alkali-tolerant Bacillus sp. YA-14

  • Park, Young-Seo (Department of Food an Biotechnology, College of Engineering, Yonsei University) ;
  • Yum, Do-Young (Department of Food an Biotechnology, College of Engineering, Yonsei University) ;
  • Hahm, Byoung-Kwon (Department of Food an Biotechnology, College of Engineering, Yonsei University) ;
  • Bai, Dong-Hoon (Department of Food Engineering, Dankook University) ;
  • Yu, Ju-Hyun (Department of Food an Biotechnology, College of Engineering, Yonsei University)
  • 발행 : 1994.03.01

초록

The xylanase from alkali-tolerant Bacillus sp. YA-14 was purified to homogeneity by CM-cellulose, Sephadex G-50, and hydroxyapatite column chromatographies. The molecular weight of the purified enzyme was estimated to be 20, 000 Da by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The purified enzyme slightly hydrolyzed carboxymethyl cellulose and Avicel, but did not hydrolyze soluble starch, dextran, pullulan, and ${\rho}-nitrophenyl-{\beta}$-D-xylopyranoside. The maximum degree of hydrolysis by enzyme for birchwood xylan and oat spelts xylan were 47 and 40%, respectively. The Michaelis constants for birchwood xylan and oat spelts xylan were calculated to be 3.03 mg/ml and 5.0 mg/ml, respectively. The activity of the xylanase was inhibited reversibly by $HgCl_2$, and showed competitive inhibition by N-bromosuccinimide, which probably indicates the involvement of tryptophan residue in the active center of the enzyme. The Xylanase was identified to be xylose-producing endo-type xylanase and did not show the enzymatic activities which cleave the branch point of the xylan structure.

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