THE C-PROTEINASE THAT PROCESSES PROCOLLAGENS TO FIBRILLAR COLLAGENS IS IDENTICAL TO THE PROTEIN PREVIOUSLY IDENTIFIED AS BONE MORPHOGENIC PROTEIN-1

Bone morphogenic protein-1 (BMP-1) was originally identified as one of several BMPs that induced new bone formation when implanted into ecto pic sites in rodents. BMP-1, however, differed from other BMPs in that it its structure was not similar to transforming growth factor beta. Instead, it had a large domain homologous to a metalloendopeptidase is olated from crayfish, an epidermal growth-factor-like domain, and thre e regions of internal sequence homology referred to as CUB domains. Th erefore, BMP-1 was a member of the ''astacin families'' of zinc-requir ing endopeptidases. Many astacins have been shown to play critical rol es in embryonic hatching, dorsal/ventral patterning, and early develop mental decisions. Here, we have obtained amino acid sequences and isol ated cDNA clones for procollagen C-proteinase (EC 3.4.24.19), an enzym e that is essential for the processing of procollagens to fibrillar co llagens. The results demonstrate that procollagen C-proteinase is iden tical to BMP-1.