Protocollagen Proline Hydroxylase from Ascaris lumbricoides

An enzyme was found in the muscle layers of Ascaris lumbricoides which was similar to the protocollagen proline hydroxylase found in chick embryos and other vertebrates in that it synthesized 14C-hydroxyprolme when incubated with 14C-proline-labeled protocollagen from chick cartilage.The Ascaris enzyme was also similar in that it required atmospheric oxygen, a-ketoglutarate, iron, and ascorbate in order to synthesize 14C-hydroxyproline.A further similarity between the Ascaris hydroxylase and the one in chick embryos was that preparations of proline-labeled protocollagen from the cuticle of Ascaris served as substrates only after they were boiled.The Ascaris hydroxylase differed from the chick embryo enzyme in that it was partially inhibited by incubation in normal atmospheric air, and the rate of the reaction increased by about 50% as the oxygen content of the gas phase was reduced to 1%.The K, for cY-ketoglutarate for the Ascaris enzyme was about 4 X lo-4 M, or about loo-fold greater than the K, for oc-ketoglutarate with the chick embryo enzyme.A further difference was that the Ascaris enzyme was not inhibited by poly-L-proline form II which competitively inhibits the chick embryo enzyme.Two distinct types of collagen are present in Ascuris lumbricoides.The collagen isolated from the cuticle differs from collagen found in vertebrates in that it has a low content of hydroxyproline, a high content of proiine, and essentially no hydroxylysine(1, 2).Also, physical measurements (2-4) and enzymatic studies (5) indicate that the molecule has an unusual conformation.