In article <[email protected]>, [email protected] says... > > I am looking for recommendations for Trypsin and > Chemotrypsin colorimetric assay, preferably not in the UV range.
The classical assay is with azocasein (e.g. Charney and Tomarelli, JBC 171 (1947) 501), this colorimetric assay is read at 440 nm. More modern assays work with Förster's resonance energy transfer: the protein is labeled with two fluorescent dyes in resonance (emission spectrum of the first overlaps the absorption spectrum of the second). As the protein is digested, distance between the dyes increases and resonance (which decreases with the 6th power of the distance) is abolished. The advantage is that you do not need to separate hydrolyzed product from non-hydrolyzed substrate and can measure while the reaction is occurring. Therefore, this type of assay is suitable for large-scale screening. _______________________________________________ Methods mailing list [email protected] http://www.bio.net/biomail/listinfo/methods
