TABLE 3.

Kinetic parameters of PPK

Reaction and source	Km (mM)	Vmax (pmol mg−1 min−1)	kcat (s−1)	kcat/Km (s−1 mM−1)
Poly P synthesis
V. cholerae	0.05	1.6 × 106	8.2	164
E. colia	2	51 × 106	59	29.5
ATP synthesis
V. cholerae	0.12b	95 × 106	65.3	544
E. colic	0.25	3.7 × 106	10.5	42
GTP synthesis
V. cholerae	2.5b	1.5 × 104	0.076	0.03
E. colic	0.63	5.7 × 104	0.088	0.14
ppppG synthesis
V. cholerae	2.3b	1.1 × 103	0.006	0.002
E. coli	0.46	9.0 × 103	0.027	0.04

^aE. coli data for poly P synthesis are from Ahn and Kornberg (1). 

^bValues for ADP or GDP. 

^cE. coli data for ATP and GTP synthesis are from Kuroda and Kornberg (16).