Killer toxin of Pichia anomala NCYC 432; purification, characterization and its exo-beta-1,3-glucanase activity

Izgu F., Altinbay D., Acun T.

ENZYME AND MICROBIAL TECHNOLOGY, vol.39, no.4, pp.669-676, 2006 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 39 Issue: 4
  • Publication Date: 2006
  • Doi Number: 10.1016/j.enzmictec.2005.11.024
  • Journal Name: ENZYME AND MICROBIAL TECHNOLOGY
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.669-676
  • Keywords: killer yeast, Pichia anomala, killer toxin, exo-beta-1,3-glucanase, SACCHAROMYCES-CEREVISIAE, TRICHODERMA-HARZIANUM, CANDIDA-ALBICANS, KLUYVEROMYCES-LACTIS, POLYACRYLAMIDE GELS, PATHOGENIC YEASTS, HANSENULA-MRAKII, CELL-WALL, PROTEIN, SYSTEM
  • Middle East Technical University Affiliated: No

Abstract

Pichia anomala NCYC 432 secretes a killer toxin which is inhibitory to a variety of yeasts including pathogenic Candida spp. The killer toxin in the culture supernatant was concentrated by ultratiltration and purified to homogenity by two successive gel filtration chromatographies with a TSK G2000SW column. Biochemical characterization of the toxin showed that it is a glycosylated protein with a molecular mass of 47 kDa and pI values of 3.4 and 3.7. The toxin showed high stability at pH values between 3 and 5.5 and up to 37 degrees C. Its N-terminal amino acid sequencing yielded the sequence GDYWDYQNDKIR which is 100% identical with that of mature exo-beta-1,3-glucanase (accession no. AJ222862) of P. anomala strain K. The toxin displayed high activity against laminarin thus showing a beta-glucanase activity. The Michaelis constants K-m and V-max for laminarin hydrolysis were 0.3 mg ml(-1) and 350 mu mol min(-1) mg(-1). (c) 2005 Elsevier Inc. All rights reserved.