TABLE 2.

Kinetic parameters of WT and mutant carrot HPPD

For clarity, mutated residues are numbered according to the Arabidopsis crystal structure 1SQD (21). The conserved residues Ser-260, Asn-275, Gln-286, Gln-300, and Gln-372 of the carrot HPPD mutated in this study correspond thus to Ser-246, Asn-261, Gln-272, Gln-286, and Gln-358 of the Arabidopsis HPPD (1SQD), respectively (see Table 1).

Enzyme	kcat	KM-HPP
	s−1	μm
WT	1.8	7.5 ± 2.5
Q358E	2.1	286 ± 22
Q286E	0.1	551 ± 76
Q272E	0.2	452 ± 63
N261D	0.3	153 ± 32
S246A	0.2	9 ± 3