title: Isolation and characterization of the K5-type yeast killer protein and its homology with an exo-beta-1,3-glucanase.
abstract: K5-type yeast killer protein in the culture supernatant of Pichia anomala NCYC 434 cells was concentrated by ultrafiltration and purified to homogeneity by ion-exchange chromatography with a POROS HQ/M column followed by gel filtration with a TSK G2000SW column. The protein migrated as a single band on discontinuous gradient SDS-PAGE and had a molecular mass of 49,000 Da. The pI value of the K5-type killer protein was measured at pH 3.7 by high voltage vertical gel electrofocusing. The result of an enzyme immuno assay revealed that it was a glycosylated protein. Its internal amino acid sequencing yielded the sequences LNDFWQQGYHNL, IPIGYWAFQLLDNDPY, and YGGSDYGDVVIGIELL, which are 100% identical to exo-beta-1,3-glucanase (accession no. AJ222862) of Pichia anomala (strain K). The purified protein was highly stable at pH values between 3 and 5.5 and temperatures up to 37 degrees C.
authors.affiliation: Department of Biological Sciences, Middle East Technical University, Ankara, Turkey. izgu@metu.edu.tr
authors.forename: Fatih
authors.initials: F
authors.lastname: Izgu
authors.forename: Demet
authors.initials: D
authors.lastname: Altinbay
mesh_terms: D000595:Amino Acid Sequence; D004795:Enzyme Stability; D043326:Glucan 1,3-beta-Glucosidase / Q000737:chemistry* / Q000302:isolation & purification* / Q000378:metabolism; D006031:Glycosylation; D006863:Hydrogen-Ion Concentration; D007526:Isoelectric Point; D055646:Killer Factors, Yeast; D008969:Molecular Sequence Data; D009183:Mycotoxins / Q000737:chemistry* / Q000302:isolation & purification* / Q000378:metabolism; D010843:Pichia / Q000201:enzymology* / Q000378:metabolism; D013696:Temperature
chemical_list: D055646:Killer Factors, Yeast; D009183:Mycotoxins; D043326:Glucan 1,3-beta-Glucosidase