. 1999 Sep;65(9):3955–3963. doi: 10.1128/aem.65.9.3955-3963.1999

TABLE 1.

Kinetic parameters for the hydrolysis of pNP-α-galactoside, melibiose, and raffinose

Substrate	AgaT		AgaN^a		RafA^a		Aga^a
Substrate	K_m (mM)	V_max (U mg⁻¹)^b	K_m (mM)	V_max (U mg⁻¹)	K_m (mM)	V_max (U mg⁻¹)	K_m (mM)	V_max (U mg⁻¹)
pNP-α-galactose	2.47	350	0.38	520	0.16	55	0.22	109
Melibiose	4.1	162	12.0	464	ND^c	ND	ND	ND
Raffinose	11.0	50	16.4	230	17.4	45	9.0	299

Comparative data from Fridjonsson et al. (16) for AgaN of B. stearothermophilus NUB3621, RafA of E. coli, and Aga of S. mutans. Hydrolyzing reactions were performed at or near the temperature optimum of activity for each enzyme: i.e., at 90°C for pNP-α-galactoside and at 80°C for raffinose and melibiose when AgaT was examined, at 75°C for AgaN, and at 37°C for RafA and Aga.

U mg⁻¹ = 1 μmol of substrate hydrolyzed per minute per mg of enzyme.

ND, not determined.