[Biosynthesis of collagen in a cell-free system from wheat germ on poly(A)-RNA isolated from membrane-bound polyribosomes of chicken embryos].

The total protein-synthesizing and collagen-synthesizing activities of poly(A)-containing RNA from the membrane-bound polyribosomes of chicken embryos were studied under various conditions in a cell-free wheat germ system. The optimal concentrations of poly(A)-RNA, mono- and bivalent cations and spermine necessary for the translation of collagen and non-collagen proteins were determined. It was shown that within a wide range of K+ and Mg2+ concentrations in a cell-free system the poly(A)-RNAs studied are very actively involved in the translation of non-collagen proteins. At the same time the bacterial collagenase-cleavable polypeptides synthesized on poly(A)-RNA from the membrane-bound polyribosomes were identified only after addition of polyamine -- spermine (40 mk/M) to the system. In this case the relative level of collagen polypeptide synthesis remains constant within a wide range of concentrations of mRNA, K+ and Mg2+ in the system. Collagen-synthesizing activity of poly(A)-RNA from membrane-bound polyribosomes in a heterologous cell-free system as compared to that of membrane-bound polyribosomes in a homologous system showed that these polyribosomes can be effectively used for isolation of collagen mRNA.