Table 1.

Apparent steady-state kinetic constants of IucC

Substrate	Kma	kcata	kcat/Km
	μm	min−1	m−1 s−1
ATPb	170 ± 20	25 ± 1	2,500
citryl-ahLysb	1,320 ± 80	29.8 ± 0.6	380
ahLys	1,900 ± 200	35 ± 1	300

^a Non-linear regression best-fit values ± S.E.

^b Substrates evaluated with saturating hydroxylamine as surrogate nucleophile.