As evidenced by sequence analysis, there is a residue insertion formed of four amino acids (12 nucleotides) at the boundary between S1 and S2 subunits of the SARS-CoV 2 S. It defines a polybasic furin cleavage site of RRAR for the human SARS-CoV 2 that was absent in human SARS-CoV, bat SARS-like CoVs, and pangolin SARS-like CoV while might be present in other species [3]. After the introduction of mutation to the residue insertion and furin cleavage site, the S1/S2 cleavage of the SARS-CoV 2 S did not longer take place. However, the SARS-CoV 2 S entry raised for VeroE6 cells and remained high in BHK cells that express human ACE. Therefore, it seems that SARS-CoV2 transmissibility does not depend on the S1/S2 cleavage.