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

2005-11-01
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.
BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY

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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.