a technique of derivatization of proline ( pro ) and 4-hydroxyproline ( hyp ) by 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole permitted the measurement of pro and hyp radioactivities , concentrations , and specific activities in the main fractions separated from cultures of fibroblast cells ( extracellular collagen and non-collagen proteins , intracellular free pro and hyp , pro- and hyp-containing peptides , procollagen , and non-collagen proteins ) .
C0033235
procollagen
C0009325
collagen