Table 1.

Summary of the IspS enzymes utilized for isoprene production

IspS source	Enzyme activitya	Isoprene productionb	Number of studies	Reference
P. alba	Km = 8.7/15.9 mM kcat = 0.03/0.034 s−1	1	12	Oku et al. 2015; Sasaki et al. 2005
P. montana (kudzu)	Km = 7.7/2.5 mM kcat = 0.088/4.4 s−1	2.3/0.3/0.25	9	Ilmen et al. 2015; Kim et al. 2016; Sharkey et al. 2005; Yang et al. 2012b; Zurbriggen et al. 2012
P. nigra	–	0.8	1	Yang et al. 2012b
E. globulus	Km = 0.2 mM kcat = 0.195 s−1	5	1	Gao et al. 2016
I. batatas	–	1.5	1	Ilmen et al. 2015
P. trichocarpa	–	3	1	Kim et al. 2016

^aDifferent K_m and K_cat values for IspS from P. alba and P. montana were obtained in different studies

^bIsoprene production of the strain engineered with P. alba was considered to be 1, and isoprene production of the strains engineered with IspS from other organisms were compared to this value