Table 4.

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			H83F/H126F			F87A			F87D			K222A
	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	1.7	7.4	0.23	160	0.31	516	117	0.41	285	80	1.2	67
L-Threonine	112	19.4	5.8	0.44	21	0.02	43	8.7	4.9	19.8	24.9	0.79	43	72	0.6

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

^amin⁻¹

^bmM