Assay Kits

Viral & bacterial Proteases


Bacterial sortase

Sortases are a family of membrane–anchored transpeptidases expressed by Gram–positive bacteria. Sortase A catalyzes the cleavage of the C-terminal recognition motif (LPXTG) of multiple structurally unrelated proteins followed by the formation of an amide bond with the peptidoglycan layer of the bacteria. Since Sortases are widely distributed among a variety of bacterial pathogens and required for virulence, Sortases represent a promising therapeutic target for the development of novel anti-infective agents.

Sortase A is extensively used as a biotechnology tool for a variety of protein modifications and immobilization by Sortase-mediated protein ligation. The transpeptidase activity of Sortase A is used to generate fusion proteins in vitro, where the recognition motif (LPXTG) is added in C-terminus of the protein of interest.

Our SensoLyte® 520 Sortase A assay allows monitoring the enzyme activity in a convenient 96 well format. As a complement, we also propose a recombinant sortase enzyme, as well as several sortase substrates.

Viral proteases

Proteases are essential for the life cycle of viruses and accordingly, they are extensively studied, i.e. to test potential inhibitors.

We constantly innovate to provide the best portfolio of quantitative assays, most being based on the FRET principle using proprietary substrates. As a world leader in FRET peptide technology we are proud to offer the same variety of long wavelength quencher and dye pairings used in our catalog peptides.

Our SensoLyte® Assay Kits enable extensive detection of protease activity to be faster, easier and compatible with HTS.

FRET substrates

FRET occurs between a peptide tagged to a donor and an acceptor when placed within 10-100Å of each other resulting in the donor’s excitation fluorescence to be quenched by the acceptor. Enzymatic hydrolysis of the peptide results in recovery of the donor fluorescence following spatial separation of the donor and acceptor upon energy transfer.

Dye (donor) Quencher (acceptor) Donor Ex/Em
SensoLyte® 390 Mca Dnp

 325/393 nm

SensoLyte® 490 EDANS DABCYL

 340/490 nm

SensoLyte® 520 5-FAM or HiLyte™ Fluor 488 QXL®520

 494/521 nm

SensoLyte® 570 5-TAMRA QXL®570

 547/574 nm

 

Fluorogenic substrates

These substrates do not require a quencher and contain a C-terminal dye that does not fluoresce until it is cleaved from the peptide (fluorescent form of dye is released).

  Dye (donor) Donor Ex/Em
SensoLyte® AMC AMC

 351/430 nm

SensoLyte® AFC AFC

 382/480 nm

SensoLyte® Rh110 Rh110

 501/527 nm