Presence of a prepiece at the NH₂-terminai end of pre-cytochrome P-450(SCC) peptide

Mild acid treatment of in vitro translated cytochrome P-450(SCC) (pre-P-450(SCQ) peptide cleaved the peptide into two fragments. Comparison of the sizes and the NH₂-terminal amino acids of the fragments with those of the corresponding fragments from mature P-450(SCC) suggested that the prepiece of pre-P-450(SCC) was present at the NH₂-terminal end of the peptide. This conclusion was confirmed by radio-sequencing of the NH₂-terminal portion of pre-P-450(SCC).