Enzymic activity of the K5-type yeast killer toxin and its characterization

Izgu, F
Altinbay, D
Sertkaya, A
K5-type yeast killer toxin secreted by P. anomala NCYC 434 cells has a broad killing spectrum. Competitive inhibiton of killer activity showed that glucans, mainly the beta-1,3 glucan, represent the primary toxin binding site within the cell wall of sensitive cells. Its hydrolytic activity on laminarin in an exo-like fashion revealed that the toxin exerts its killing effect by exo-beta-1,3-glucanase activity. Its specific activity on laminarin was 120U/mg, and the Michaelis constants K-m, and V-max for laminarin hydrolysis were 0.25mg/ml and 370 mu mol/min/mg. The toxin exerted its cytocidal effect after 2 h contact with the target cells. Production of the toxin by the cells was induced only when they were grown in culture media rich in beta-glucan sources, and the addition of glucose increased the specific production rate. The enzymic activity of the toxin was fully inhibited by Hg+2, but increased with some other metal ions, most of all by Pb+2.


Killer toxin of Pichia anomala NCYC 432; purification, characterization and its exo-beta-1,3-glucanase activity
Izgu, Fatih; Altinbay, Demet; Acun, Tolga (Elsevier BV, 2006-08-02)
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...
Isolation and characterization of the K5-type yeast killer protein and its homology with an exo-beta-1,3-glucanase
Izgu, F; Altinbay, D (Informa UK Limited, 2004-03-01)
K5-type yeast killer protein in the culture supernatant of Pichia anomala NCYC 434 cells was concentrated by ultrafiltration and purified to homogenity 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 discontinous gradient SDS-PAGE and had a molecular mass of 49000 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 immu...
Overexpression of serine alkaline protease encoding gene in Bacillus species: performance analyses
Çalık, Pınar; Ozdamar, TH (Elsevier BV, 2003-12-02)
Bacillus species carrying subC gene encoding serine alkaline protease (SAP) enzyme were developed in order to increase the yield and selectivity in the bioprocess for SAP production. For this aim, subC gene was cloned into pHV1431 Escherichia coli-Bacillus shuttle vector, and transferred into nine host Bacillus species, i.e. B. alvei, B. amyloliquefaciens, B. badius, B. cereus, B. coagulans, B. firmus, B. licheniformis, B. sphaericus and B. subtilis. The influence of the host Bacillus species on SAP product...
Fermentation and oxygen transfer characteristics in serine alkaline protease production by recombinant Bacillus subtilis in molasses-based complex medium
Calik, G; Pehlivan, N; Ozcelik, IS; Çalık, Pınar; Ozdamar, TH (Wiley, 2004-11-01)
Serine alkaline protease (SAP) production in a complex medium based on physically pretreated molasses by recombinant Bacillus subtilis carrying pHV1431::subC gene is described. The effects of oxygen transfer were investigated in 3.5 dm(3) bioreactor systems with controls for agitation rate, dissolved oxygen, pH, temperature, and foam formation under two different agitation rates, ie N = 500 and 750 min(-1), and four different air flow rates, ie Q/V-R = 0.2, 0.5, 0.7, and 1.0 vvm, at a molasses concentration...
Cloning, characterization and heterologous expression of the aspartokinase and aspartate semialdehyde dehydrogenase genes of cephamycin C-producer Streptomyces clavuligerus
Tunca, S; Yilmaz, EI; Piret, J; Liras, P; Özcengiz, Gülay (Elsevier BV, 2004-09-01)
Carbon flow through the lysine branch of the aspartate biosynthetic pathway is a rate-limiting step in the formation of cephamycin C, a broad spectrum P-lactam antibiotic produced by Streptomyces clavuligerus. In this study, genes which encode the enzymes catalyzing the first two steps of the aspartate pathway, ask (aspartokinase) and asd (aspartate semialdehyde dehydrogenase), in S. clavuligerus NRRL 3585 were cloned and sequenced. Nucleotide sequencing and codon preference analysis revealed three complete...
Citation Formats
F. Izgu, D. Altinbay, and A. Sertkaya, “Enzymic activity of the K5-type yeast killer toxin and its characterization,” BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY, pp. 2200–2206, 2005, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/66737.