One unit of trypsin activity corresponded to 1 [micro]mol 4-nitroaniline
liberated in 1 min/mL extracellular enzymatic extract, based on the extinction coefficient of the substrate ([epsilon]407 = 8,200/M/cm).
(MNA, 97%) and 4-nitroaniline
(pNA, 984) were purchased from Alfa Aesar.
Biodegradation products of Acid Orange 7 and Disperse Orange 3, by white rot fungus, Pleurotus ostreatus, were identified as 4-hydroxybenzenesulfonic acid, benzenesulfonic acid, 1,2-naphthoquinone, 4-nitrophenol, nitrobenzene, 4-nitroanisole, and 4-nitroaniline
It describes the use of [gamma]-glutamyl-4nitroanilide as a substrate that is cleaved to form the easily measured 4-nitroaniline
The precision, in terms of CV of the absorbance of twelve repetitive recordings (390 nm, 150 [micro]L of buffered solutions of 4-nitroaniline per well), was [+ or -]0.
The liberation of 4-nitroaniline was observed at 390 nm for at least 15 min with a sampling rate of 120 data points per min.
Because of the peculiarities of the coupled assay, the remaining part contributes to the unwanted background absorbance attributed to 4-nitroaniline at 390 nm [15,24,25].