Table 1. NEPS and MLPL in vitro activities.

Summary of activities observed in in vitro assays with ISY and 8OG (Fig. 3 and figs. S16 to S20). Cyclisation refers to formation of nepetalactol isomers from the reactive ISY product; dehydrogenation refers to formation of nepetalactone isomers from corresponding nepetalactols. Ticks (✓), activity observed; question mark (?), possible activity, not verified; tilde (~), trace activity; double tick (✓✓), in vitro activity supported by in planta gene expression profiling data (only tested for N. mussinii).

Enzyme		Cyclization			Dehydrogenation
		cis-trans	cis-cis	trans-cis	cis-trans	cis-cis	trans-cis
Nm	NEPS1	?			✓	✓	✓✓
Nc	NEPS1	?			✓	✓	✓
Nm	NEPS2
Nc	NEPS2
Nm	NEPS3		✓✓			~
Nc	NEPS3A		✓			✓
Nm	NEPS3B		✓			~
Nm	NEPS4			✓✓	✓	?	~
Nc	NEPS4			✓	✓	?	~
Nm	NEPS5	?			✓✓	✓	✓
Nc	NEPS5	?			✓	✓	✓
Nm	MLPL	✓✓
Nc	MLPLA	✓
Nc	MLPLB	✓