Table 1. Comparative account of catalytic parameters (pH optima and K_m) of W. somnifera tropine forming tropinone reductase (WsTR-I) with other plant TRs reported from plants.

Enzyme	pH Optima	Km (mM)	Reference
WsTR-I*	5.7	1.27	Present study
StTR-I*	6.0	0.188	Kaiser et al. [46]
StTR-II*	6.4	0.033	Keiner et al. [57]
DsTR-I*	7.0	0.117	Nakajima et al. [41]
DsTR-II*	7.0	0.048	Nakajima et al. [41]
DsTR-I#	6.4	1.3	Portsteffen et al. [58]
DsTR-II#	6.4	0.11	Portsteffen et al. [58]
HnTR-I*	5.9	1.01	Hashimoto et al. [35]
HnTR-II*	5.9	0.034	Hashimoto et al. [35]
HnTR-II#	5.8	0.035	Drager et al. [46]
CoTR-I*	8.0	3.29 (at pH 6.4)	Brock et al. [48]

^*Recombinant protein expressed in E. coli.

^#Native protein purified from the plant source.