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Science 27 October 1967:
Vol. 158. no. 3800, pp. 492 - 494
DOI: 10.1126/science.158.3800.492
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Articles

Intracellular Pool of Unhydroxylated Polypeptide Precursors of Collagen

Rajendra S. Bhatnagar 1, Darwin J. Prockop 1, and Joel Rosenbloom 1

1 Departments of Medicine and Biochemistry, University of Pennsylvania, and Philadelphia General Hospital, Philadelphia 19104

The hydroxyproline and hydroxylysine in collagen are synthesized by an apparently unique pathway in which proline and lysine are hydroxylated after they are incorporated into a large polypeptide precursor of collagen called protocollagen. When the hydroxylation of protocollagen in isolated tissues is intermittently interrupted, hydroxylation can occur after complete polypeptides are released from ribosomal complexes. Cartilage from chick embryos was incubated with the iron chelator agr,agr'-dipyridyl for 2 hours to inhibit protocollagen hydroxylase, and then the inhibition was reversed by transferring the tissues to medium containing ferrous iron and no agr,agr'-dipyridyl. "Pulse labeling" of the tissues during these two periods indicated that both the accumulated protocollagen and the polypeptides synthesized after reversal of the inhibition were hydroxylated at the same rate. Even when no measures are taken to inhibit the hydroxylation of protocollagen, most of the hydroxyproline in collagen is probably synthesized after complete protocollagen polypeptides are released from ribosomes.


THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
Alteration of Protein Synthesis in Cartilage by a Synthetic Double-Stranded Polyribonucleotide.
M. Clair and L. Wadell (1971)
Journal of Dental Research 50, 1072-1079
   PDF »
Collagen Polypeptides: Normal Release from Polysomes in the Absence of Proline Hydroxylation.
E. Lazarides and L. N. Lukens (1971)
Science 173, 723-725
   Abstract »    PDF »
Recent Progress in Collagen Research.
G. R. Martin (1971)
Journal of Dental Research 50, 268-274
   PDF »


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Science. ISSN 0036-8075 (print), 1095-9203 (online)