In 1962, through analysis of the radioactivity incorporated into collagen using a tritiated version of the amino acid proline, Stone and Meister discovered that vitamin C is used as a co-substrate by peptidyl-prolyl hydroxylase, an enzyme that catalyzes the selective modification of proline to hydroxyproline.onsequently, the lack of vitamin C results in the formation of non-functional collagen in blood vessels and bones, which accounts for most of the severe bone and blood vessel related symptoms.