Table 2.

	relative specific activitya			τb			relative quantum yieldc
	octanal	decanal	dodecanal	octanal	decanal	dodecanal	octanal	decanal	dodecanal
wt	100	100	100	0.06	0.43	0.05	100	100	100
Y151A	0.027	0.042	0.85	0.10	0.41	0.05	0.02	0.05	0.92
Y151D	0.13	0.40	0.36	0.09	0.50	0.05	0.08	0.41	0.36
Y151F	4.2	9.8	7.2	0.05	0.46	0.05	4.5	14	7.4
Y151I	15	96	31	0.06	0.45	0.04	16	91	35
Y151K	2.3	0.71	0.46	0.10	0.44	0.06	1.3	0.68	0.02
Y151R	10	9.5	22	0.05	0.43	0.06	13	9.5	19
Y151T	1.0	6.5	3.4	0.07	0.43	0.07	0.79	6.5	2.4
Y151 V	13	13	18	0.19	0.50	0.05	3.5	10	17
Y151W	0.006	0.011	0.012	0.07	0.46	0.09	0.005	0.01	0.007

^aSpecific activities of purified protein were determined by the standard FMNH₂ injection assay (28). Wild-type protein had a specific activity of 5.45 × 10¹², 8.96 × 10¹³, and 1.58 × 10¹¹ quanta s⁻¹ mg⁻¹ using octanal, decanal, or dodecanal, respectively.

^bThe decay rate was based on the following calculation $I(t)=I_0{2}^{-t/t_{1/2}}$; where t_1/2=τ ln 2. Half-lives were determined based on the time for bioluminescence to decay from the decrease from 80% of the maximum light measurement to 40%.

^cTotal quantum yield was determined over the first 100 s of exponential decay. The relative yield was determined by normalizing values for each of the mutants to that of the wild-type enzyme.