Furin fundamentals
There’s no direct evidence for the lab leak hypothesis – and the biochemistry of the virus might not tell us much about it
The dinner-party bores who once proclaimed so confidently on hanging chads (in 2000) and subprime mortgages (2008) now have a new way to announce their perspicacity: ‘Ah, but what about the furin cleavage site? A smoking gun, if you ask me.’
It would be as if the chatterati had suddenly become obsessed with finer points of aromatic substitution or heterogeneous catalysis. I admit that I would previously have supposed furin to be some derivative of the furan molecule, whereas in fact it is an enzyme with the recondite job of converting as-synthesised proteins to their active form – a job conducted by cleaving bits off the precursor proteins.
This is, of course, all about Covid – specifically, about the site snipped by furin (or related protease enzymes) in the spike protein of the Sars-CoV-2 coronavirus. This transformation enables the spike protein to bind to the ACE2 receptor of human cells, initiating viral attachment and infection.