Table 2.

Kinetic parameters of the retro-aldol cleavage reactions catalysed by wild type and mutant eTAs with the threo and erythro isomers of l-threonine.

Substrate	WT			H126N			H126F			H83N			H83F
	kcata	Kmb	$\frac{k_{\mathit{\text{cat}}}}{K_m}$	kcat	Km	$\frac{k_{\mathit{\text{cat}}}}{K_m}$	kcat	Km	$\frac{k_{\mathit{\text{cat}}}}{K_m}$	kcat	Km	$\frac{k_{\mathit{\text{cat}}}}{K_m}$	kcat	Km	$\frac{k_{\mathit{\text{cat}}}}{K_m}$
L-allo-Threonine	213	0.24	887	469	0.96	488	541	0.2	2705	77	1.7	45	3.7	7	0.53
L-Threonine	112	19.4	5.8	262	61	4	360	1.7	212	17	38	0.4	1.2	7	0.17

All parameters are the average of three independent determinations, with the range between values being always less than ± 5%.

^amin⁻¹

^bmM