Table 1.

Specific activity (units mg⁻¹ = μmol min⁻¹ mg⁻¹ mg⁻¹) of BlArap42B from B. animalis subsp. lactis BL-04 (wild-type and mutants) and RiArap42B from R. intestinalis M50/1 toward 5 mmpNP-substrates

The activity was measured at 37 °C in 40 mm sodium citrate (pH 6.5) and 0.005% Triton X-100. All enzymes including the mutants showed no detectable activity toward pNP-β-d-Glcp, pNP-α-l-Araf, and pNP-β-d-Xylp.

Substrate	BlArap42B				RiArap42B
	Wild-type	W345F	W358H	W345F/W358H
pNP-α-l-Arap	79.0 ± 0.7	2.7 ± 0.1	5.9 ± 0.1	0.1 ± 0.0	55.2 ± 2.0
pNP-β-d-Galp	0.1 ± 0.0	NDa	NDa	NDa	0.1 ± 0.0
pNP-β-d-Fucp	1.9 ± 0.0	NDa	0.7 ± 0.0	NDa	2.6 ± 0.1

^a ND, not detected (<0.05 units mg⁻¹).