here , the same fibroblasts were incubated in the presence of 1.53 mm cis-4-hydroxyproline , an analogue of proline , or in the presence of 0.3 mm alpha , alpha'-dipyridyl , an inhibitor of prolyl hydroxylase , so that the cells synthesized procollagen which could not assume a triple helical conformation characteristic of procollagen .
C0016030
fibroblasts
C0007634
cells