Prolyl 4-hydroxylase subunit beta (P4HB)

Prolyl 4-hydroxylase subunit beta (P4HB) is the beta component of the prolyl 4-hydroxylase enzyme complex, which catalyzes the post-translational hydroxylation of proline residues in collagen precursors, a modification essential for the formation of stable collagen triple helices[2][4]. The beta subunit is identical to protein disulfide-isomerase, a multifunctional enzyme that assists in the formation, breakage, and rearrangement of disulfide bonds in the endoplasmic reticulum, and is essential for proper protein folding[2][4]. The enzyme functions as an α2β2 tetramer (two alpha and two beta subunits)[1]. It is widely expressed, tightly regulated, and plays key roles not only in collagen biosynthesis but also in maintaining redox homeostasis and protein quality control. Alterations of P4HB function or expression are implicated in several diseases, including fibrosis, cancer, and certain rare genetic syndromes such as HIDEA syndrome[1].

Other names

Protein disulfide-isomerasePDIA1PDIβ-subunit of prolyl 4-hydroxylase

Inhibition of P4HB disrupts disulfide bond formation and protein folding in the endoplasmic reticulum, potentially leading to accumulation of misfolded proteins and cellular stress[2]. Inhibit prolyl 4-hydroxylase activity, affecting collagen maturation and deposition[3].