TABLE 4.

Relative activities of Os9BGlu31 wild type and the catalytic acid/base mutants E169Q and E169A, catalytic nucleophile mutant E387A, and H386T mutant

Os9BGlu31 wild type and mutants were purified with immobilized metal affinity chromatography and Q-Sepharose chromatography, respectively.

Acceptor	Relative activity
	Wild type	E169Q	E169A	E387A	H386T
	nmol of 4NP min−1 mg−1 protein
Buffer alone	14.8 ± 0.6	3.4 ± 0.3	0.3 ± 0.02	0.008 ± 0.0001	2.7 ± 0.3
Ferulic acid	133.4 ± 8.3	18 ± 1.1	1.7 ± 0.05	0.007 ± 0.0003	61.3 ± 0.4
Caffeic acid	100.8 ± 0.1	13.6 ± 0.9	1.6 ± 0.07	0.007 ± 0.0004	49.4 ± 5.1
Sinapic acid	93.3 ± 3.2	23.6 ± 1.6	1.8 ± 0.10	0.012 ± 0.0003	38.8 ± 1.2
4-Hydroxybenzoic acid	86.4 ± 6.1	11.6 ± 0.5	1.5 ± 0.01	0.008 ± 0.0004	30.0 ± 0.6
Vanillic acid	81.5 ± 5.7	10.2 ± 1.0	1.6 ± 0.06	0.011 ± 0.0004	19.9 ± 1.5
trans-Cinnamic acid	78.7 ± 7.6	11.1 ± 1.1	1.5 ± 0.02	0.008 ± 0.0001	19.5 ± 2.1
Syringic acid	83.1 ± 6.4	10.4 ± 0.5	1.3 ± 0.03	0.012 ± 0.001	19.0 ± 2.0
Benzoic acid	77.8 ± 7.8	11.0 ± 0.1	1.4 ± 0.02	0.01 ± 0.001	14.4 ± 0.2
4-Coumaric acid	81.1 ± 7.3	14.1 ± 1.1	1.6 ± 0.03	0.01 ± 0.0003	28.3 ± 2.5
Isovanillic acid	68.3 ± 6.8	10.0 ± 0.7	1.1 ± 0.03	NMa	22.0 ± 1.0
Catechin	38.8 ± 3.9	4.8 ± 0.2	0.5 ± 0.01	NM	NDb
Dihydroxybenzoic acid	50.6 ± 5.1	2.7 ± 0.1	0.8 ± 0.01	NM	10.7 ± 1.1
1-Napthalene acetic acid	53.9 ± 5.4	2.5 ± 0.1	1.1 ± 0.004	NM	6.8 ± 0.2
Scopoletin	16.8 ± 0.5	0.8 ± 0.02	0.7 ± 0.003	NM	5.0 ± 0.2
Indole acetic acid	43.9 ± 1.8	5.1 ± 0.5	0.9 ± 0.03	NM	4.9 ± 0.1
Apigenin	39.6 ± 2.0	11.2 ± 1.2	0.5 ± 0.03	NM	6.9 ± 0.4
2,4-Dichlorophenoxyacetic acid	44.8 ± 3.0	9.7 ± 0.3	1.1 ± 0.01	NM	3.8 ± 0.1

^a NM, not measured.

^b ND, not detected.