procollagen-proline 4-dioxygenase complex
Definition
Target type: cellularcomponent
A protein complex that catalyzes the formation of procollagen trans-4-hydroxy-L-proline and succinate from procollagen L-proline and 2-oxoglutarate, requiring Fe2+ and ascorbate. Contains two alpha subunits that contribute to most parts of the catalytic sites, and two beta subunits that are identical to protein-disulfide isomerase. [PMID:14500733, PMID:7753822]
The procollagen-proline 4-dioxygenase complex, also known as prolyl 4-hydroxylase, is a multi-enzyme complex responsible for the hydroxylation of proline residues in collagen. This hydroxylation is critical for the stability and proper folding of collagen. The complex comprises several subunits, each contributing to its overall function:
1. **α(I) subunit:** This subunit is the catalytic subunit and contains the active site where the hydroxylation reaction takes place. It binds to the procollagen substrate and utilizes molecular oxygen and 2-oxoglutarate as cofactors for the hydroxylation process.
2. **α(II) subunit:** This subunit is also a catalytic subunit and shares a similar structure and function with the α(I) subunit. It contributes to the overall enzymatic activity of the complex.
3. **β subunit:** This subunit is a non-catalytic subunit that plays a crucial role in the stabilization and assembly of the complex. It also contributes to the proper binding of the procollagen substrate.
4. **γ subunit:** This subunit is a non-catalytic subunit involved in the regulation of the complex activity. It interacts with the other subunits, influencing their catalytic efficiency and substrate affinity.
The procollagen-proline 4-dioxygenase complex localizes primarily to the endoplasmic reticulum (ER), the cellular compartment where collagen synthesis occurs. The ER membrane provides a platform for the complex assembly and efficient interaction with its substrate, procollagen. The complex is anchored to the ER membrane via its interaction with the ER chaperone protein, Hsp47, which facilitates proper folding and secretion of collagen.
The cellular component of the procollagen-proline 4-dioxygenase complex is therefore a multi-protein assembly embedded within the ER membrane. This complex plays a vital role in the biosynthesis of collagen, a major structural protein essential for maintaining the integrity of connective tissues.'
"
Proteins (2)
| Protein | Definition | Taxonomy |
|---|---|---|
| Prolyl 4-hydroxylase subunit alpha-1 | A prolyl 4-hydroxylase subunit alpha-1 that is encoded in the genome of human. [PRO:DNx, UniProtKB:P13674] | Homo sapiens (human) |
| Protein disulfide-isomerase | A protein disulfide-isomerase that is encoded in the genome of human. [PRO:DNx, UniProtKB:P07237] | Homo sapiens (human) |
Compounds (5)
| Compound | Definition | Classes | Roles |
|---|---|---|---|
| alpha-ketoglutaric acid | 2-oxoglutaric acid : An oxo dicarboxylic acid that consists of glutaric acid bearing an oxo substituent at position 2. It is an intermediate metabolite in Krebs cycle. | oxo dicarboxylic acid | fundamental metabolite |
| 2,5-pyridinedicarboxylic acid | 2,5-Pyridinedicarboxylic acid: RN given refers to parent cpd isocinchomeronic acid : A pyridinedicarboxylic acid carrying carboxy groups at positions 2 and 5. | pyridinedicarboxylic acid | |
| isoliquiritigenin | chalcones | antineoplastic agent; biological pigment; EC 1.14.18.1 (tyrosinase) inhibitor; GABA modulator; geroprotector; metabolite; NMDA receptor antagonist | |
| galangin | 5,7-dihydroxyflavonol: antimicrobial from the twigs of Populus nigra x Populus deltoides; structure in first source galangin : A 7-hydroxyflavonol with additional hydroxy groups at positions 3 and 5 respectively; a growth inhibitor of breast tumor cells. | 7-hydroxyflavonol; trihydroxyflavone | antimicrobial agent; EC 3.1.1.3 (triacylglycerol lipase) inhibitor; plant metabolite |
| ascorbic acid | Ascorbic Acid: A six carbon compound related to glucose. It is found naturally in citrus fruits and many vegetables. Ascorbic acid is an essential nutrient in human diets, and necessary to maintain connective tissue and bone. Its biologically active form, vitamin C, functions as a reducing agent and coenzyme in several metabolic pathways. Vitamin C is considered an antioxidant. L-ascorbate : The L-enantiomer of ascorbate and conjugate base of L-ascorbic acid, arising from selective deprotonation of the 3-hydroxy group. Required for a range of essential metabolic reactions in all animals and plants. L-ascorbic acid : The L-enantiomer of ascorbic acid and conjugate acid of L-ascorbate. vitamin C : Any member of a group of vitamers that belong to the chemical structural class called butenolides that exhibit biological activity against vitamin C deficiency in animals. The vitamers include L-ascorbic acid and its salt, ionized and oxidized forms. | ascorbic acid; vitamin C | coenzyme; cofactor; flour treatment agent; food antioxidant; food colour retention agent; geroprotector; plant metabolite; skin lightening agent |