Table 2.

Catalytic constants and substrate specificities of purified X. polymorpha GH78

Substrate	Sp act (U/mg)	Km (μM)	kcat (s−1)	kcat/Km (s−1 M−1)
p-Nitrophenyl α-l-rhamnopyranoside	24.4a	971	32.9	3.4 × 104
p-Nitrophenyl α-l-arabinofuranoside	1.5	NDb	ND	ND
Naringine	1.2	ND	ND	ND
p-Nitrophenyl β-d-glucopyranoside	0.1	ND	ND	ND
p-Nitrophenyl β-d-cellobioside	0.07	ND	ND	ND
Methyl ferulate	7.3a	80	9.3	1.2 × 105
Methyl p-coumarate	4.1a	21	6.2	2.9 × 105
Methyl sinapate	2.8a	103	3.7	3.6 × 104
Ethyl ferulate	2.1a	94	2.6	2.7 × 104
Methyl caffeate	0.92a	151	1.4	9.3 × 103
Veratric acid ethyl ester	0.01a	78	0.1	1.3 × 103
Veratric acid methyl ester	0.01a	62	0.1	1.6 × 103
Methyl-6-O-sinapoyl glucopyranoside	1.2	ND	ND	ND
Methyl-6-O-feruloyl glucopyranoside	2.2	ND	ND	ND
Chlorogenic acid	0.3	ND	ND	ND
p-Nitrophenyl acetate	0.09	ND	ND	ND
Dibenzoyl tartrate	0	ND	ND	ND

^aCalculated as V_max/protein amount.

^bND, not determined.