Parvulin

Although parvulin has no homology with larger prolyl isomerases such as cyclophilin and FKBP, it does share structural features with subdomains of other proteins involved in preparing secreted proteins for export from the cell.

[3] Although parvulin is as active as the larger prolyl isomerases against a short proline-containing test peptide, it has lower relative activity against biological substrates, possibly because the larger molecules have a higher ability to bind the substrate peptide.

[5] Absence of Pin1 activity in humans has also been implicated in the folding and processing of the amyloid precursor protein, whose degradation product is the cytotoxic peptide amyloid beta implicated in Alzheimer's disease.

In humans the locus of this parvulin resides on chromosome Xq13 and encodes two protein species, Par14 and Par17.

[7] Par17,[8][9] which is exclusively expressed in hominids and humans, is an N-terminal extended version of Par14 and results from alternative transcription initiation.