[Comparative study of ceruloplasmin biosynthesis in various cell-free systems]

Some peculiarities of mRNA translation of ceruloplasmin (CP) from rat liver were investigated, using three cell-free protein biosynthesis systems (wheat embryo extracts, rabbit reticulocyte lysates and Zajdela ascite hepatoma extracts). It was shown that reticulocyte lysates and tumour cell extracts synthesize full-size CP mRNA translation products, whose molecular mass is close to that of mature CP molecules, i. e., 122-132 kD. Wheat embryo extracts synthesize the NH2-terminal fragment of the CP molecule (Mr = 84 kD). Addition of liver membrane fractions to wheat embryo extracts translating CP mRNA results in the reconstitution of proteolytic steps of CP maturation.