Isoform 7 of Aspartyl/asparaginyl beta-hydroxylase

Aspartyl/asparaginyl beta-hydroxylase (ASPH), isoform 7, is a 203-amino-acid protein encoded by the ASPH gene in humans (UniProt: Q12797-7). This enzyme catalyzes post-translational hydroxylation of aspartyl and asparaginyl residues in target proteins, a modification important for protein folding and stability in the endoplasmic reticulum and secretory pathway.

ASPH is broadly distributed across tissues and participates in protein quality control mechanisms. While UniProt records no specific disease associations for this isoform, the protein has been implicated in various cellular processes related to protein maturation and secretion.

In Alzheimer's disease, ASPH isoform 7 shows reduced expression in post-mortem AD brain relative to age-matched controls, with a mean log2 fold-change of −0.44 across analyzed subcellular fractions (Chaparral AD proteomics). This modest downregulation suggests a potential role in the pathophysiology of neurodegeneration, though the functional significance of reduced ASPH levels in AD remains to be elucidated.