Table 1. Kinetic parameters for ZmALDH12 and PpALDH12.

Saturation curves for NAD⁺ and NADP⁺ were measured in 100 mM pyrophosphate buffer (pH 7.5) using 0.3 mM GSAL, saturation curves for aldehyde substrates were measured with 3.0 mM NAD⁺. Kinetic constants K_m and k_cat including their standard error values were determined using GraphPad Prism 5.0 software. The lower k_cat values for NAD⁺ (indicated by asterisks) compared to those for GSAL result from using a fixed sub-saturating GSAL concentration in the saturation of the enzymes by NAD⁺. n.d. - not determined

Substrate	ZmALDH12			PpALDH12			ZmALDH12 D226A
	Km	kcat	kcat/Km	Km	kcat	kcat/Km	Km	kcat	kcat/Km
	(μM)	(s−1)	(s−1M1)	μM)	(s−1)	(s−1M−1)	μM)	(s−1)	(s−1M1)
NAD+	185 ± 14	*3.1 ± 0.1	1.7 ± 0.2 ×104	227 ± 14	*0.17 ± 0.01	7.4 ± 0.8 × 102	119 ± 7	*1.7 ± 0.1	1.4 ± 0.1 × 104
NADP+	2872 ± 360	0.8 ± 0.1	2.7 ± 0.5 × 102	3066±186	0.05 ± 0.01	1.4 ± 0.1 × 101	71 ± 6	1.5 ± 0.1	2.1 ± 0.1 × 104
GSAL	198 ± 21	6.8 ± 0.5	3.4 ± 0.6 × 104	228 ± 40	0.44 ± 0.05	1.9 ± 0.6 × 103	266 ± 34	3.6 ± 0.3	1.3 ± 0.3 × 104
GRSAL	84 ± 5	1.9 ± 0.2	2.3 ± 0.4 × 104	82 ± 6	0.30 ± 0.02	3.7 ± 0.6 × 103	n.d.	n.d.	n.d.
AASAL	173 ± 12	0.04 ± 0.02	2.0 ± 0.2 × 102	211 ± 13	0.005 ± 0.001	2.6 ± 0.2 × 101	n.d.	n.d.	n.d.
D-GAP	1860±99	0.4 ± 0.1	2.1 ± 0.2 × 102	n.d.	n.d.	n.d.	n.d.	n.d.	n.d.