Table 2. Kinetic properties for the bioluminescence reactions of Gluc variants.

	Half-Life (s)	Mass (μg)	Reaction Time* (s)	Relative Quantum Yield (ϕ) (% GlucY)	Relative Turnover Rate (% GlucY)
GlucY	7	10 ± 0.25	15	100	100
MonstaY	4	10 ± 0.65	4	62	374
4lucY	†	10 ± 0.95	167	398	9
Tgy	67	10 ± 1.21	104	90	22
tMonY	51	20 ± 0.45	200	5	23
t4Y	101	12 ± 0.34	179	9	16

The quantum yield (ϕ) is a measure of luminescence emission per mole of native substrate (coelenterazine). The turnover rate measures how quickly coelenterazine is utilized in the reaction. Both values are expressed relative to GlucY for more straightforward comparison. All samples were measured in assay buffer (see Methods section).

^*Bioluminescent emission integrated until 90% of maximum was obtained.

^†4lucY half-life was too long to be determined by regression analysis of the data in Fig. 4A.