Hydrolases;
Acting on peptide bonds (peptidases);
Cysteine endopeptidases
Reaction(IUBMB)
Autocatalytically cleaves itself from the polyprotein of the foot-and-mouth disease virus by hydrolysis of a Lys!Gly bond, but then cleaves host cell initiation factor eIF-4G at bonds -Gly!Arg- and -Lys!Arg-
Comment
Best known from foot-and-mouth disease virus, but occurs in other aphthoviruses and cardioviruses. Destruction of initiation factor eIF-4G has the effect of shutting off host-cell protein synthesis while allowing synthesis of viral proteins to continue. The tertiary structure reveals a distant relationship to papain and, consistent with this, compound E-64 is inhibitory. Type example of peptidase family C28.
