description
General Background : 4-HYDROXY-L-PROLINE "4-hydroxyproline" residues contribute to the stability of the : Collagens "collagen" triple helix. : Collagens "Collagen" is a major constituent of extracellular matrix protein. Other proteins containing 4-hydroxyproline include : elastin, the complement component C1q, and : HS01552-MONOMER. Most of the 4-hydroxyproline in animals is biosynthesized by post-translational modification of appropriate : PRO residues by : HS04122-MONOMER and : HS01693-MONOMER during the biosynthesis and maturation of collagen. The 4-hydroxyproline released during : Collagens "collagen" degradation cannot be reutilized and is degraded instead. About this Pathway This major mammalian pathway for 4-hydroxyproline degradation has been demonstrated in liver and kidney mitochondria. All the enzymes in this pathway are expressed in human liver, kidney, pancreas and small intestine . The first step of the pathway, the oxidation of : 4-HYDROXY-L-PROLINE to : PYRROLINE-HYDROXY-CARBOXYLATE is an electron transfer reaction, very likely catalyzed by : MONOMER66-34410, which like : HS01958-MONOMER is located in the inner mitochondrial membrane. The two distinct enzymes : HS01958-MONOMER and : MONOMER66-34410 catalyze the first step of : PROUT-PWY and : HYDROXYPRODEG-PWY respectively, and have little or no substrate crossover. However, the downstream metabolites of both pathways are degraded by a series of analogous reactions of biochemical similarity . The substrate : PYRROLINE-HYDROXY-CARBOXYLATE exists in spontaneous equilibrium with its open chain form : L-4-HYDROXYGLUTAMATE_SEMIALDEHYDE . The second enzyme, : CPLX-6746, shared with : PROUT-PWY, catalyzes the irreversible oxidation of : L-4-HYDROXYGLUTAMATE_SEMIALDEHYDE to : L-ERYTHRO-4-HYDROXY-GLUTAMATE . After the deamination step catalyzed by : CPLX66-370, the hydroxyl group of : CPD-15015 permits an aldol cleavage to produce : PYRUVATE and : GLYOX catalyzed by : CPLX66-315 . : GLYOX "Glyoxylate" is a reactive compound that is enzymatically converted to less active derivatives. It is reduced to : GLYCOLLATE by : CPLX66-474 in the liver

external resources
NCBI:142337
BIOCYC:HUMAN_HYDROXYPRODEG-PWY
PUBMED:13681370
PUBMED:22207577
PUBMED:500817
PUBMED:12660328
PUBMED:18287100
PUBMED:21998747
PUBMED:16756993

genes
GOT2 , ALDH4A1 , PRODH2 , HOGA1 ,