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Enzyme Assays |
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PDQ Protease Assay™
The PDQ™ Protease Assay is a unique colorimetric assay used to detect protease activity in aqueous samples. The proprietary substrate responds to a wide range of proteases including serine, metallo, aspartate and cysteine proteases such as collagenase, proteinase K, papain, pepsin, bromelin, ficin, trypsin and chymotrypsin. PDQ™ can be used with just a few simple steps to measure protease activity and requires no centrifugation. The substrate is a cross-linked matrix containing protein substrate and a dye-protein conjugate. Protease activity is detected spectrophotometrically with increasing optical density proportional to increasing enzyme activity and can detect nanogram quantities. Each kit is supplied with a trypsin solution for generating standard curves (BAEE equivalent units). PDQ™ is supplied in 48 ready-to-use plastic vials.
The graph on the right shows the time-course degradation of the PDQ™ Protease Assay substrate by papain, chymotrypsin, proteinase K, and collagenase. Duplicate reactions were incubated at 37°C and 0.2 N NaOH was added to the vials to stop the reaction at the indicated times. The absorbance at 450nm was measured by transferring the reaction mixture to spectrophotometric cuvettes. The results of this experiment show the increased absorption over time due to protelytic degradation of the substrate, and the ability of the assay to detect a wide range of proteases.
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