[Isolation and purification of 3C-proteinase from the poliomyelitis virus. Identification of an active form of the enzyme].

All the forms of 3C protease previously found were isolated and purified. A 3D polymerase's fragment covalently bound with 3C protein does not affect the specific proteolytic activity of the enzyme, whereas the elimination of 26 N-terminal amino acid residues of 3C protease leads to its inactivation.