Prolyl-4-Hydroxylase Alpha Polypeptide II (P4Ha2)

Prolyl 4-hydroxylase catalyzes the posttranslational formation of 4-hydroxyproline in collagens. The vertebrate enzyme is a tetramer of 2 alpha subunits and 2 beta subunits. The beta subunit (P4HB) is an unusual multifunctional polypeptide identical to protein disulfide isomerase. P4HA2 is one of at least 2 alpha subunit isoforms. This gene encodes a component of prolyl 4-hydroxylase, a key enzyme in collagen synthesis composed of two identical alpha subunits and two beta subunits. The encoded protein is one of several different types of alpha subunits and provides the major part of the catalytic site of the active enzyme. In collagen and related proteins, prolyl 4-hydroxylase catalyzes the formation of 4-hydroxyproline that is essential to the proper three-dimensional folding of newly synthesized procollagen chains.