how is procollagen converted to tropocollagen
proÂ·colÂ·laÂ·gen. Soluble precursor of tropocollagen formed by fibroblasts and other cells in the process of collagen synthesis; unstable type III procollagen is associated with Ehlers-Danlos syndrome type IV.proÂ·colÂ·laÂ·gen/ (-kolÂ´ah-jen) the precursor molecule of collagen, synthesized in the fibroblast, osteoblast, etc., and cleaved to form collagen extracellularly.