Engineering the substrate binding site of the hyperthermostable archaeal endo-β-1,4-galactanase from Ignisphaera aggregans

Table 1 Michaelis–Menten kinetic parameters and thermal denaturation points

	K_m (mg ml⁻¹)	k_cat (s⁻¹)	k_cat/K_m \((\mathrm{ml }\,{\mathrm{mg}}^{-1}\, {\mathrm{ s}}^{-1})\)	T_m (°C)
IaGal WT	0.47 ± 0.08	34 ± 2	73 ± 13	105
Variant 1	0.38 ± 0.09	14 ± 4	36 ± 13	102
Variant 2	0.48 ± 0.08	16 ± 3	34 ± 9	101
Variant 3	2.3 ± 0.6	28 ± 15	12 ± 7	103
Variant 4	2.7 ± 0.3	20 ± 6	7 ± 2	103
BlGal	0.94 ± 0.15	2.5·10² ± 0.1·10²	2.6·10² ± 0.4·10²	53
MtGal	1.0 ± 0.4	3.6·10² ± 0.3·10²	3.5·10² ± 1.3·10²	N/A

The parameters are on lupin galactan in 50 mM NaOAc pH 5.0 and 0.01% Triton X-100, at 70 °C for IaGal WT and variants and 30 °C for BlGal and MtGal. The 95% confidence interval is calculated for the parameters. The measured thermal denaturation midpoint (T_m) is presented for comparison

ISSN: 2731-3654