CAS: 2304802-09-1

The main protease Mpro is a key protein in the lifecycle of the SARS-CoV-2 virus. Mpro cleaves the viral polyproteins at the C-terminal end of a glutamine residue in recognition sequences containing Leu-Gln-(Ser, Ala, Gly) motifs (Rut et al, 2020).  As SARS-CoV-2 MPro has no closely related homologues in humans, it represents an attractive drug target (Ullrich and Nitsche, 2020). In summary, the Mpro protease is a chymotrypsin-like cysteine protease, requires homodimerisation for proteolytic activity, cleaves the viral polyproteins in 11 distinct sites, exclusively after a glutamine residue. A fluorogenic substrate for Mpro assays is Ac-Abu-Tle-Leu-Gln-AMC.The protein amount or better its concentration in solution is quantified using either A280 (absorption at 280 nm with its specific absorption coefficient) or using the Bradford assay (uses the dye Coomassie Brilliant Blue). Both of these methods quantify the total amount of protein in a sample, no matter what the oligomerization state is.