prolyl 4-hydroxylase subunit alpha-3 (4-PH alpha-3, procollagen-proline, 2-oxoglutarate-4-dioxygenase subunit alpha-3, P4HA3)
Jump to navigation
Jump to search
Function
- catalyzes the post-translational formation of 4- hydroxyproline in -Xaa-Pro-gly- sequences in collagens & other proteins
procollagen L-proline + 2-oxoglutarate + O2
<-->
procollagen trans-4-hydroxy-L-proline + succinate + CO2
Cofactor: iron, ascorbate
Structure
- heterotetramer of two alpha-3 chains & two beta chains (the beta chain is the multi-functional PDI)
- N-glycosylation plays no role in the catalytic activity
- belongs to the P4HA family
- contains 1 PKHD (prolyl/lysyl hydroxylase) domain
- contains 1 TPR repeat
Compartment
endoplasmic reticulum lumen (probable)
Alternative splicing
named isoforms=2
Expression
- highly expressed in placenta, liver & fetal skin
- weakly expressed in fetal epiphyseal cartilage, fetal liver, fibroblast, lung & skeletal muscle
Pathology
- expressed also in fibrous cap of carotid atherosclerotic lesions