FIG. 2.

Isomaltose-producing activity in the culture filtrate and cell extract of A. nidulans. The 35-fold-concentrated culture filtrate (CF) and the cell extract (CE) were incubated with 0.5% maltose in 40 mM acetate buffer (pH 5.5) at 45°C for 2 h, and the reaction products were analyzed by TLC. The volumes of CF and CE used for the reactions were 48 and 10 μl, corresponding to 2 ml and 200 μl of the original culture suspension, respectively. The culture filtrate was concentrated by Ultrafree MC (Millipore). Glucose (G), maltose (M), maltotriose (G3), maltotetraose (G4), maltopentaose (G5), isomaltose (I), panose (P), and isomaltotriose (IG3) were used as standards (Std).