Table 5.

Limit of detection (LOD) and limit of quantification (LOQ) for hCE1 using partially purified enzyme. Substrate activities ([S] = 50 µM) were measured at 37°C in sodium phosphate buffer (100 mM, pH = 8, 0.1 mg/mL BSA) containing 1% DMSO. The signal-to-noise ratio was determined by taking the ratio of the mean signal to the standard deviation of the background signal, each performed as quadruplicates of a single experiment.

	Kinetic Modea	Endpoint mode
		1 hour	4 hours	24 hours
4-MOMMP
LODb	3.9 ng	0.06 ng	0.03 ng	0.008 ng
LOQc	16 ng	2.0 ng	0.12 ng	0.03 ng
CMNA
LODb	2.0 ng	0.98 ng	3.9 ng	0.06 ng
LOQc	3.9 ng	7.8 ng	(−)d	(−)d

^aKinetic measurements were taken at 30 second intervals for 30 minutes.

^bLOD is the lowest measurement where S/N > 3.

^cLOQ is the lowest measurement where S/N > 9.

^dThe (−) indicates that there were insufficient data points above S/N > 9 to generate a linear curve.