[Biosynthesis of collagen and other proteins on tightly and loosely bound polyribosomes from chick embryos].
Free polyribosomes and polyribosomes bound to endoplasmic membranes were isolated from 10-day-old chick embryos by differential centrifugation. The tightly and loosely bound polyribosomal fractions were isolated from the membrane-bound polyribosomes using 0,5 M KCl. The synthesis of collagen and non-collagen proteins on the polyribosomes were studied in a homologous cell-free system. It was shown that the polyribosomes tightly bound to the membranes possess a lower protein-synthesizing activity as compared to free and loosely bound polyribosomes. The amount of bacterial collagenase-cleaved polypeptides in the protein product synthesized on the polyribosomes tightly and loosely bound to the memranes and on free polyribosomes is 31, 23 and 9%, respectively. The data obtained suggest that the loosely bound polyribosomes are actively involved in collagen synthesis and that this fraction is not a contamination of free polyribosomes in the preparations of totally bound polyribosomes. The role of tightly and loosely bound polyribosomes in the formation of the membrane polyribosomal complex is discussed.
D000818:Animals; D002462:Cell Membrane / Q000502:physiology; D002642:Chick Embryo; D003094:Collagen / Q000096:biosynthesis*; D003012:Microbial Collagenase; D011132:Polyribosomes / Q000378:metabolism*; D014176:Protein Biosynthesis
D003094:Collagen; D003012:Microbial Collagenase
Biosintez kollagena i drugikh belkov na prochno i neprochno sviazannykh poliribosomakh iz kurinykh embrionov.