Table 2.

Kinetic Parameters for Substrate Hydrolysis by PalH from Erwinia rhapontici

Substrate	Vmaxa	Km (mM)	kcat min−1
Maltose: 4-O-α-D-glucopyranosyl-D-glucopyranose	1.01 ± 0.02	8.58 ± 0.34	51
Maltitol: 4-O-α-D-glucopyranosyl-D-sorbitol	0.24 ± 0.01	7.31 ± 0.58	12
Trehalose: 1-O-α-D-glucopyranosyl-α-glucopyranoside	0.51 ± 0.01	6.59 ± 0.37	26
Trehaluloseb: 1-O-α-D-glucopyranosyl-α-D-fructose	0.47 ± 0.01	3.63 ± 0.31	24
Sucrose: 1-O-α-D-glucopyranosyl-β-D-fructofuranoside	0.31 ± 0.02	22.11 ± 3.37	16
Turanose: 3-O-α-D-glucopyranosyl-D-fructose	0.46 ± 0.03	10.04 ± 1.21	23
Maltulose: 4-O-α-D-glucopyranosyl-D-fructose	0.53 ± 0.01	1.75 ± 0.19	27
Leucrose: 5-O-α-D-glucopyranosyl-D-fructose	0.44 ± 0.03	5.31 ± 0.81	22
Palatinose: 6-O-α-D-glucopyranosyl-D-fructofuranoside	0.70 ± 0.01	2.52 ± 0.12	35
Sophorose (2-O-β-D-glucopyranosyl-D-glucopyranose) NDHc
Laminaribiose (3-O-β-D-glucopyranosyl-D-glucopyranose) NDH
Cellobiose (4-O-β-D-glucopyranosyl-D-glucopyranose) NDH
Gentiobiose (6-O-β-D-glucopyranosyl-D-glucopyranose) NDH
Lactose (4-O-β-D-galactopyranosyl-D-glucopyranose) NDH
Melibiose (6-O-α-D-galactopyranosyl-D-glucopyranose) NDH

^aExpressed as μmol substrate hydrolyzed mg protein⁻¹ min⁻¹. All assays were carried out spectrophotometrically at 25 °C.

^bCompounds in boldface are sucrose isomers.

^cNDH No detectable hydrolysis.