Table 5.

Catalytic rates of 4-diphosphocytidyl-2-C-methyl-d-erythritol kinases

Substrate	Specific activity, μmol⋅mg−1⋅min−1
	Peppermint	Tomato	E. coli
4-Diphosphocytidyl-2-C- methyl-d-erythritol	—	33	34
Isopentenyl phosphate (this study)	—	<0.000002	<0.000002
Isopentenyl phosphate (ref. 26)	≈0.0001*	—	≈0.001*

^*Estimated from data by Lange and Croteau (26) with the assumption of a 1% enzyme purity for the E. coli enzyme and a 0.1% purity for the peppermint enzyme that had not been purified. The electropherogram in Fig. 2 of ref. 26 shows a visible band for the recombinant E. coli protein (lane 5).