Serine Endopeptidase Inhibitor (SPI)

A serine endopeptidase inhibitor is a molecule—either endogenous or exogenous—that binds to and inhibits the activity of serine endopeptidases, also known as serine proteases. These enzymes cleave peptide bonds in proteins, utilizing a catalytic triad typically composed of serine, histidine, and aspartic acid residues at their active site. The inhibitors play crucial roles in regulating physiological processes by preventing uncontrolled proteolysis. Serine endopeptidase inhibitors function by binding to the active site or another regulatory region of the enzyme, thereby blocking substrate access or altering enzyme conformation. There are two main mechanisms: trapping inhibition and tight-binding inhibition. Dysregulation can lead to diseases such as emphysema, coagulopathies, inflammatory disorders, neurodegenerative diseases, and increased susceptibility to infections.

Other names

Serine Protease Inhibitor

Inhibition of serine endopeptidase activity through binding to the active site or regulatory regions, blocking substrate access or altering enzyme conformation. This can occur through trapping inhibition (covalent complex formation) or tight-binding inhibition (high-affinity non-covalent binding).