Purification and Properties of Extracellular Chitinases from the Parasitic Fungus Isaria japonica

概要

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Two chitinases(P-1 and P-2)induced with colloidal chitin were purified from the culture supernatant of Isaria japonica by chromatography on DEAE Bio-Gel, chromatofocusing and gel filtration with Superdex 75pg. The enzymes were electrophoretically homogeneous and estimated to have a molecular mass of 43, 273(±5)for P-1 and 31, 134(±6)for P-2 by MALDI-MS. The optimum pH and temperature was 3.5-4.0 and 50℃ for P-1 and 4.0-4.5 and 40℃ for P-2. P-1 acted against chitosan 7B(degree of deacetylation, 65-74%)=glycol chitin>colloidal chitin=chitosan 10B(degree of deacetylation, above 99%)and P-2 against chitosan 7B>glycol chitin=chitosan 10B>colloidal chitin in order of activity. The products of hydrolysis of chitin and chitosan hexamer were analyzed by MALDI-MS. The products from the chitin hexamer obtained with P-1 were almost all dimers with only a small amount of trimer whereas those obtained with P-2 were mainly trimers with some dimer and tetramer. No hydrolysis of chitosan hexamer was observed. High homology in the amino-terminal sequence for chitinase P-1 was exhibited by chitinases from Trichoderma harzianum, Candida albicans and Saccharomyces cerevisiae in the range of 48-39%. The highest homology for Chitinase P-2 was shown by an endochitinase from Metarhizium anisopliae of 66%, while 44% homology was exhibited by chitinases of Leguminosae plants.
社団法人日本生物工学会の論文
2001-12-25