Protease Assay Kit

A kit suitable for quantitative array of a wide variety of proteases in biological samples, utilizing FTC-casein as a substrate. Enzyme activities that have been detected with this assay kit include: chymotrypsin, elastase, plasminogen, PRONASE^® Protease, subtilisin, thermolysin, and trypsin.

This Protease Assay Kit is suitable for the quantitative determination of protease activity in biological samples. This kit has been tested for its suitability in detecting a wide variety of proteases, including serine proteases (trypsin, chymotrypsin, thrombin, plasmin, elastase, subtilisin), cysteine proteases (papain, cathepsin B) and acid proteases (thermolysin, pepsin). Each kit provides sufficient reagents for 200 assays. When used as recommended, this kit is ~100-fold more sensitive than either the casein-gel assay or casein A₂₈₀ assay. The Protease Assay Kit can detect ~10 ng/ml of protease when a 24 h incubation is used. The sensitivity can be enhanced by up to 3-fold by using a fluorometer (excitation 490 nm and emission 525 nm) rather than a spectrophotometer to detect the proteolytic end products.

Assay Time: 3 h

• FTC-casein should be stored at -20°C and is stable for one year from the date of purchase. FTC-casein stored at 4°C is stable for 2-3 days. Several freeze-thaw cycles will lead to a minor increase in the background fluorescence, so following initial thawing, we suggest that this reagent be divided into 5 aliquots. FTC-casein is light sensitive and should be protected from light.

• Protease positive control should be stored at -20°C. As with many proteases, trypsin is susceptible to autolysis and you may notice a reduction in trypsin activity with time, even if stored at -20°C.

• Incubation buffer and assay buffer may be stored at 4°C or -20°C.

A Fluorescent-Casein Substrate, Incubation Buffer, Assay Buffer Trypsin Standard, and a user protocol.

Twining, S.S. 1984. Anal. Biochem.143, 30.
Wiesner, R., et al. 1982. Anal. Biochem.121, 290.

CALBIOCHEM is a registered trademark of Merck KGaA, Darmstadt, Germany

PRONASE is a registered trademark of Merck KGaA, Darmstadt, Germany

Toxicity: Multiple Toxicity Values, refer to MSDS (O)