The polyribosomal synthesis of collagen

Abstract

The formation of collagen, on polyribosomes has been studied. Collagen was identified its characteristic content of hydroxyproline, which is derived metabolically by from proline. [ 14C]Proline was injected into chick embryos and nascent collagen was measured in sucrose density gradients by the isolation of protein-bound [ 14C]hydroxyproline. The results indicate that collagen is synthesized on very large polysomes. Ribonuclease, puromycin and dodecyl sulfate studies indicate that the nascent peptide chains already contain hydroxyproline suggesting that hydroxylation occurs prior to complete peptide chain assembly. There is suggestive evidence that the large polysomes may result from the aggregation of nascent collagen peptide chains.