TABLE 2.

Apparent kinetic constants of cellobiose dehydrogenase from S. rolfsii for several electron donors^a

Substrate	Kinetic constants
	Km (mM)	kcat (s−1)	kcat/Km (mM−1 · s−1)
Cellobiose	0.12	27	225
Thiocellobiose	2.3	27	11.7
Cellotriose	0.49	26	53.1
Cellotetraose	0.60	24	40.0
Cellopentaose	0.54	24	44.4
Lactose (equilibrated)	2.4	26	10.8
β-Lactose (70 to 75%)	2.0	26	13.0
α-Lactose	>54	<17	<0.32
Xylobiose	5.4	27	5.0
Maltose	240	0.8	3.3 × 10−3
Glucose	1,250	1.5	1.2 × 10−3

^aKinetics were measured using the standard DCIP assay at pH 4.0 and 25°C; protein was determined using the BCA method.