Studies on the Underhydroxylated Basement Membrane Procollagen Synthesized by Rat Parietal Yolk Sacs in the Presence of α, α'-Dipydridyl

Abstract

Rat embryo parietal yolk sacs synthesized and secreted underhydroxylated [¹⁴C]proline-labeled basement membrane procollagen when incubated in the presence of the iron chelator α, α'-dipyridyl and [¹⁴C]proline. Upon reduction and sodium dodecyl sulfate-agarose gel filtration, this procollagen eluted as a discrete peak of labeled material close to the position of the β components of type I collagen. Secreted underhydroxylated procollagen contained interchain disulfide bonds and was completely degraded by a 6 hr treatment with α-chymotrypsin at 4 d`C. Results from 4 hr incubations indicated that the distribution of ¹⁴C-procollagen between tissue and medium was unaffected by the presence of α, α'-dipyridyl, but analysis of results from pulse-label and chase experiments revealed that underhydroxylated procollagen was secreted at less than half the rate of control procollagen.