Protocollagen proline hydroxylase in normal liver and in hepatic fibrosis.
Academic Article
Overview
Research
Identity
Additional Document Info
Other
View All
Overview
abstract
Previous observations indicated that the hydroxyproline in collagen is synthesized by the hydroxylation of proline which has been incorporated into a large polypeptide precursor of collagen called protocollagen, and that the hydroxylation of protocollagen is one of the terminal reactions in the intracellular synthesis of collagen. Significant levels of protocollagen proline hydroxylase activity were demonstrated both in normal rat liver and in a single specimen of human liver. The enzymatic activity in rat and human liver was similar to protocollagen proline hydroxylase isolated from chick embryos in that it was inhibited by poly-L-proline II, and it required ascorbate, -ketoglutarate, and ferrous iron. When hepatic fibrosis was produced in rats with carbon tetrachloride or with a choline-deficient diet, liver levels of protocollagen proline hydroxylase increased over 4-fold. In all of the experiments the increase in protocollagen proline hydroxylase activity occurred more promptly and it was more marked than the increase in collagen hydroxyproline. 1969, The Williams & Wilkins Company. All rights reserved.
