IDENTIFICATION OF RAPIDLY LABELED, SMALL MOLECULAR-WEIGHT HYDROXYPROLINE-CONTAINING PEPTIDES IN DEVELOPING MOUSE LIMBS INVITRO AND INVIVO

Limbs from embryonic mice labeled with radioactive proline either in vitro or in vivo readily synthesized hydroxyproline-containing peptides, the majority of which were of a molecular size less than intact collagen α-chains. The hydroxyproline isomers detected in these peptides included trans-3-hydroxyproline, trans-4-hydroxyproline, and cis-4-hydroxyproline. The abundance of small peptide material containing these hydroxyproline isomers is unusual in that as much as 85% is present in such forms at 10 days gestation when the limb is initially forming and 35% at 14 days when the limb is fully developed. The identification of small molecular weight hydroxyproline-containing peptides in limbs removed from embryos labeled in vivo indicate they are not organ culture artifacts. © 1979.