FIG. 4.

Patterns of hydrolysis of soluble starch and maltooligosaccharides by LAMY. (A) Products from soluble starch (0.2% [wt/vol]). The reaction (0.2 U ml⁻¹) was done at 30°C and at pH 8.5 in 50 mM Tris-HCl buffer. Samples were taken at the indicated intervals and boiled for 5 min to terminate the reaction. The products formed were analyzed by TLC with butanol-pyridine-water (6:3:4 [vol/vol]) as the solvent system. Std denotes authentic maltooligosaccharides. (B) Maltooligosaccharides in the G2 to G15 range (0.2% [wt/vol]), shown in lanes 2 through 15, respectively were hydrolyzed for 15 min by LAMY (0.2 U ml⁻¹) under the standard conditions of the assay. The products formed were boiled for 5 min, and then they were analyzed by TLC with butanol-pyridine-water (9:2:2 [vol/vol]) as the solvent system. (C) Cleaved-bond distribution in the hydrolysis of maltooligosaccharides G7 and G8 by LAMY. All reactions were performed at 40°C and at pH 8.5 in 50 mM Tris-HCl buffer. The products formed were boiled for 5 min, and then they were quantified by HPLC, as described in Materials and Methods. Solid symbols (•) represent nonreducing ends of the substrates. The numerals indicate the cleavage frequency of the bond. Catalytic efficiency for each substrate is expressed as k₀/K_m.