Background. Inhibition of prolyl hydroxylase (EC 1.14. 11.2)[procollagen-L-proline, 2- oxog1utarate: oxygen oxidoreductase (4-hydroxylating) 12 is of therapeutic interest because the enzyme is necessarily involved3 in the biosynthesis of the collagen deposited during life- threatening fibroses. During these fibrotic states the involved organ or tissue becomes unbearably congested with inappropriately large amounts of collagen. Chronic liver ...