Comparison of chitinase isozymes from yam [Dioscorea opposita] tuber: Enzymatic factor controlling the lytic activity of chitinases

• Published in: Bioscience, biotechnology, and biochemistry Vol. 64; no. 4; pp. 723 - 730
• Main Authors: Arakane, Y. (Yamaguchi Univ. (Japan). Faculty of Agriculture), Hoshika, H, Kawashima, N, Fujiya Tsujimoto, C, Sasaki, Y, Koga, D
• Format: Journal Article
• Language: English
• Published: Tokyo Japan Society for Bioscience, Biotechnology, and Agrochemistry 01.04.2000; Japan Society for Bioscience Biotechnology and Agrochemistry; Oxford University Press
• Subjects: AGENT PATHOGENE; Agronomy. Soil science and plant productions; Animals; Biological and medical sciences; Bombyx - enzymology; CHITINASE; chitinases; Chitinases - immunology; Chitinases - isolation & purification; Chitinases - metabolism; DEFENCE MECHANISMS; DIOSCOREA OPPOSITA; Economic plant physiology; ENZIMAS; ENZYME; ENZYMES; Fundamental and applied biological sciences. Psychology; Fungal plant pathogens; Fusarium - metabolism; FUSARIUM OXYSPORUM; Hydrogen-Ion Concentration; Immunoblotting - methods; ISOENZIMAS; ISOENZYME; ISOENZYMES; Isoenzymes - immunology; Isoenzymes - isolation & purification; Isoenzymes - metabolism; Kinetics; Liliaceae - enzymology; MECANISME DE DEFENSE; MECANISMOS DE DEFENSA; Nutrition. Photosynthesis. Respiration. Metabolism; ORGANISMOS PATOGENOS; PATHOGENS; Pathology, epidemiology, host-fungus relationships. Damages, economic importance; Phytopathology. Animal pests. Plant and forest protection; plant self-defense; PR-proteins; QUITINASA; TUBERCULE; TUBERCULO; TUBERS; yam (Diosscorea opposita THUNB); Chitinase; Monocotyledones; Fusarium oxysporum; Plant pathogen; Enzyme; Isozyme; Host agent relation; Pathogenesis related protein; Dioscoreaceae; Fungi; Enzymatic activity; Glycosidases; Angiospermae; Hydrolases; Defense mechanism; Spermatophyta; Fungi Imperfecti; Tuber plant; O-Glycosidases; Thallophyta; Dioscorea opposita
• ISSN: 0916-8451; 1347-6947
• DOI: 10.1271/bbb.64.723

To evaluate the anti-pathogen activity of chitinases, we developed a new method for measuring the lytic activity, and investigated the correlation of the lytic activity with the enzymatic properties by using four chitinase isozymes, Chitinases E, F, H1 and G, which had been purified from yam tubers by column chromatography. Chitinases E, F and H1 had high lytic activity against the plant pathogen, Fusarium oxysporum, but Chitinase G did not. Chitinase E, which is the family 19 chitinase, was similar to Chitinases F and G in its antigenecity, but not to Chitinase HI or H2. Chitinases H1 and H2 were recognized by the anti-Bombyx mori chitinase antibody, suggesting that Chitinases H1 and H2 are family 18 chitinases like B. mori chitinases. Chitinases E, F and H1 had two optimum pH ranges of 3-4 and 7.5-9 toward glycolchitin, but Chitinase G had only one optimum pH value of 5. Chitinases E, F and H1 had higher affinity to the polymer substrate, glycolchitin, than Chitinase G. These results suggest that the lytic activity of plant chitinases may be related to the chitin affinity and probably to the characteristic optimum pH value, or two values, but not related to its classification. The correlation of the lytic activity of a chitinase isozyme with its elicitor specificity is also discussed