TABLE 1.

Kinetic parameters on gelatinized starch and enzymatic activity on raw starch of lactobacilli α-amylases^a

Strain and substrate	Kinetic parameter on gelatinized starch			Initial-activity rate (U mol−1) on starch granules
	Km (g liter−1)	kcat (s−1)	kcat/Km (s−1 g−1 liter−1)
L. amylovorus
Soluble potato starch	1.97 ± 0.11	3.1 × 104	1.6 × 104	1,578 ± 86
Corn starch	5.24 ± 0.31	1.4 × 103	2.6 × 102	133 ± 13
Amylopectin	2.87 ± 0.29	1.3 × 103	4.5 × 102	607 ± 18
Amylose	8.00 ± 0.50	1.8 × 103	2.2 × 102	3,020 ± 259
Maltoheptaoside	0.19 ± 0.02b	1.4 × 107	7.7 × 107	ND
L. plantarum
Soluble potato starch	1.92 ± 0.09	3.8 × 103	2.0 × 104	98 ± 5
Corn starch	13.00 ± 1.31	2.4 × 102	1.8 × 101	5 ± 0.3
Amylopectin	5.10 ± 0.40	1.9 × 102	3.8 × 101	16 ± 0.9
Amylose	5.00 ± 0.59	3.2 × 102	6.3 × 101	127 ± 10
Maltoheptaoside	0.22 ± 0.02b	1.2 × 107	5.4 × 107	ND

^aError in the model adjustment to the Michaelis-Menten equation is as follows (L. plantarum and L. amylovorus, respectively): on soluble potato starch, 8 × 10⁻⁸ and 10⁻⁷; on corn starch, 4 × 10⁻⁹ and 2 × 10⁻⁸; on amylopectin, 4 × 10⁻⁹ and 2 × 10⁻⁸; on amylose, 2 × 10⁻⁸ and 10⁻⁷; on maltoheptaoside, 3 × 10⁻² and 2 × 10⁻¹. ND, not determined.

^bK_m in millimoles per liter.