Definition: In this task, you're given a paragraph from the research paper and your task is to generate a suitable title for the research paper based on the given paper. Under 100 words is a good title length.
Input: The 3C-like protease (3CL pro ) of severe acute respiratory syndrome associated coronavirus (SARS-CoV) is vital for SARS-CoV replication and is a promising drug target. Recombinant 3CL pro was expressed in Pichia pastoris GS115 as a 42 kDa protein that displayed a K m of 15 ± 2 lM with Dabcyl-KTSAVLQSGFRKME-Edans as substrate. Purified 3CL pro was used for inhibition and kinetic assays with seven flavonoid compounds. The IC 50 of six flavonoid compounds were 47-381 lM. Quercetin, epigallocatechin gallate and gallocatechin gallate (GCG) displayed good inhibition toward 3CL pro with IC 50 values of 73, 73 and 47 lM, respectively. GCG showed a competitive inhibition pattern with K i value of 25 ± 1.7 lM. In molecular docking experiments, GCG displayed a binding energy of -14 kcal mol -1 to the active site of 3CL pro and the galloyl moiety at 3-OH position was required for 3CL pro inhibition activity.

Flavonoid-mediated inhibition of SARS coronavirus 3C-like protease expressed in Pichia pastoris