PA_hPAP21_like: Protease-associated domain containing proteins like the human secreted glycoprotein hPAP21 (human protease-associated domain-containing protein, 21kDa). This group contains various PA domain-containing proteins similar to hPAP21. Complex N-glycosylation may be required for the secretion of hPAP21. The significance of the PA domain to hPAP21 has not been ascertained. It may be a protein-protein interaction domain. At peptidase active sites, the PA domain may participate in substrate binding and/or promoting conformational changes, which influence the stability and accessibility of the site to substrate.
Jiyao W et al.(2023). "The conserved domain database in 2023.",