Pierce™ Protease Assay Kits are an ideal choice for performing routine assays necessary during the isolation of proteases, or for identifying the presence of contaminating proteases in protein samples. These protease assays are also ideal for studying pH or temperature vs. activity profiles of purified proteases.

• No corrosive precipitants used
• Entire assay can be run in microplates
• Highly sensitive, faster and uses half the sample of unmodified casein-based protease assays
• Measure multiple samples simultaneously in ELISA plate readers
• Time/temperature/pH easily manipulated to optimise sensitivity

The colorimetric Protease Assay Kit uses fully succinylated casein as substrate for this assay. Hydrolysis of this readily soluble casein substrate in the presence of protease results in the release of peptide fragments with free aminoterminal groups. Evidence of protease activity is obtained by reaction of these peptides with trinitrobenzene sulphonic acid (TNBSA), followed by measurement of the absorbance increase that is due to the formation of yellow coloured TNB-peptide adducts. A standard protease is provided, allowing the user to determine the concentration of protease in samples undergoing analysis.

The Fluorescent Protease Assay Kit is based on a FITC-labelled casein. This sensitive assay can be used in either FRET or FP modes.