Glucoamylase produced by Scytalidium thermophilum was purified 80-fold by DEAE-cellulose, ultrafiltration and CM-cellulose chromatography. The enzyme is a glycoprotein containing 9.8% saccharide, pI of 8.3 and molar mass of 75 kDa (SDS-PAGE) or 60 kDa (Sepharose 6B). Optima of pH and temperature with starch or maltose as substrates were 5.5/70 degrees C and 5.5/65 degrees C, respectively. The enzyme was stable for 1 h at 55 degrees C and for about 8 d at 4 degrees C, either at pH 7.0 or pH 5.5. Starch, amylopectin, glycogen, amylose and maltose were the substrates preferentially hydrolyzed. The activity was activated by 1 mmol/L Mg2+ (27%), Zn2+ (21%), Ba2+ (8%) and Mn2+ (5%). Km and vlim values for starch and maltose were 0.21 g/L, 62 U/mg protein and 3.9 g/L, 9.0 U/mg protein, respectively. Glucoamylase activity was only slightly inhibited by glucose up to a 1 mol/L concentration.

Departamento de Biologia Faculdade de Filosofia Ciências e Letras de Ribeirão Preto Universidade de São Paulo 14 040 901 Ribeirão Preto São Paulo Brasil

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Nature. 1970 Aug 15;227(5259):680-5 PubMed

Biotechnol Appl Biochem. 1990 Feb;12(1):63-78 PubMed

Biochem Biophys Res Commun. 1981 Feb 12;98(3):792-9 PubMed

Crit Rev Food Sci Nutr. 1995 Sep;35(5):373-403 PubMed

Planta. 1966 Jun;72(2):155-61 PubMed

Nature. 1949 Jul 2;164(4157):27-9 PubMed

Crit Rev Biochem Mol Biol. 1989;24(4):329-418 PubMed

Cell. 1977 Dec;12(4):1133-41 PubMed

Biochem J. 1976 Feb 1;153(2):321-7 PubMed

Folia Microbiol (Praha). 2000;45(3):207-10 PubMed

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