Différence entre les mécanismes de la biosynthèse induite des iso-cytochromes c

摘要: According to the work of Slonimski, Acher, Pere, Sels & Somlo (1963) , normal yeast contains two molecular species cytochrome c, iso-1 and iso-2, latter being minor component; except for a few amino acid residues, primary structures these single-chain proteins are similar. These workers postulated that precursor protein without haem iso-2-cytochrome c exists in cell before induction by oxygen, this is specific repressor synthesis iso-1-cytochrome polypeptide chain. In present paper, three experiments reported which support possibility c. (1) At beginning induction, rate incorporation radioactive acids into (moles given incorporated per mole corresponding residues iso-cytochrome c) was lower than 30 40%, indicating at least part did not come from an exchangeable pool. (2) 5-Methyltryptophan inhibited formation both iso-1- c; however, more sensitive presence analogue synthesis; (3) phenylalanine- tyrosine-requiring mutant, suppressed absence acids, whereas iso-l-cytochrome severely affected. data can be understood if non-induced cells.