N-Terminal Region of GbIspH1, Ginkgo biloba IspH Type 1, May Be Involved in the pH-Dependent Regulation of Enzyme Activity

Table 1

Kinetic parameters of IspH proteins.

Source	Reducing system		Kinetics parameters				Reference
			(min^−1)^b	S.A.; (μmolmin^−1mg^−1)	(μM)	(µM^−1 min^−1)
E. coli	NADPH^a	0.4	11.6	0.31	15	0.8	[11]
	DT-MV	0.4	604	16.3	19.7	30.7	[21]
	DT-MDQ^c	0.4	1125	30.4	31.6	35.6
A. aeolicus	DT-MV		222	6.6	590	0.4	[22]
P.  falciparum	DT-MV		124	2.1	39	3.2	[23]
	NADPH			10.3
GbIspH1-full	DT-MV	0.17	369	6.7	17.3	21.3	This work
GbIspH1-truncated		0.18	347	7.2	14.9	23.3

NADPH was added with flavodoxin/flavodoxin reductase or ferredoxin/ferredoxin-NADP⁺ reductase.
MW was estimated based on the peptide sequence. IspH from E.  coli, 37.0 kDa; A. aeolicus, 31.8 kDa; P.  falciparum, 58.8 kDa.
6,7-dihydro-2,11-dimethyldipyrido1,2-a:2,1-c pyrazinium dibromide (MDQ) is a MV analog.