Glucoamylase (exo-1,4-α-d-glucan glucanohydrolase, EC 3.2.1.3) is the major starch-degrading enzyme secreted by the phytopathogenic fungus Colletotrichum gloeosporioides

摘要: Activity assays based on selective product detection were used to identify the classes of amylase present in culture filtrates phytopathogen Colletotrichum gloeosporioides. When transferred from a glucose medium containing starch as sole carbohydrate, C. gloeosporioides secreted amylolytic activity into liquid shake cultures starting 2-3 d after inoculation, and produced levels up 0.45 IU ml-1 (assayed by p-hydroxybenzoic acid hydrazide — PAHBAH reducing sugar method), about 20 times higher than comparable glucose-grown controls, suggesting that (or degradation product) was required induce synthesis. In four separate experiments, ratio total production method) glucose-specific oxidase GO 1.0 most samples filtrate, clearly demonstrating major enzyme is glucoamylase (exo-1,4-α-d-glucan glucanohydrolase, EC 3.2.1.3, synonym amylogluco-sidase). On one occasion only (a 7 sample experiment) evidence obtained for α-amylase (endo-1,4-α-d-glucan 3.2.1.1) also being filtrate (PAHBAH/GO 1.37); presence this confirmed native polyacrylamide gel electrophoresis using starch-iodine stain.