Proteolytic Maturation of the Turnip‐Yellow‐Mosaic‐Virus Polyprotein Coded in vitro Occurs by Internal Catalysis

Abstract
The genomic RNA of turnip yellow mosaic virus is translated in vitro into 2 major high-MW proteins, the larger of which (MW 195,000) undergoes post-translational cleavage. The mechanism of formation of the primary cleavage products (MW 120,000 and 78,000) of the 195,000-MW protein was examined. The fact that cleavage partly occurs at a rate insensitive to dilution of the 195,000-MW protein is suggestive of an intramolecular mechanism of proteolytic maturation.