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Some characteristics of two forms of glucoamylase(glucan 1,4-α-glucosidase, EC 3. 2. 1. 3) purified fromAspergillus coreanus NR 15-1 were investigated. The enzymeswere produced on a solid, uncooked wheat bran medium ofA. coreanus NR 15-1 isolated from traditional Korean Nuruk.Two forms of glucoamylase, GA-I and GA-II, were purified tohomogenity after 5.8-fold and 9.6-fold purification, respectively,judged by disc- and SDS-polyacrylamide gel electrophoresis.The molecular mass of GA-I and GA-II were estimated to be62 kDa and 90 kDa by Sephadex G-100 gel filtration, and64 kDa and 91 kDa by SDS-polyacrylamide gel electrophoresis,respectively. The optimum temperatures of GA-I and GA-IIwere 60oC and 65oC, respectively, and the optimum pHwas 4.0. The activation energy (Ea value) of GA-I and GA-IIwas 11.66 kcal/mol and 12.09 kcal/mol, respectively, andthe apparent Michaelis constants (Km) of GA-I and GA-IIfor soluble starch were found to be 3.57 mg/ml and 6.25 mg/ml, respectively. Both enzymes were activated by 1 mMMn2+ and Cu2+, but were completely inhibited by 1 mM Nbromosuccinimide.The GA-II was weakly inhibited by 1 mMp-CMB, dithiothreitol, EDTA, and pyridoxal 5'-phosphate,but GA-I was not inhibited by those compounds. Both enzymeshad significant ability to digest raw wheat starch and raw ricestarch, and hydrolysis rates of raw wheat starch by GA-I andGA-II were 7.8- and 7.3-fold higher than with soluble starch,respectively.