Scytalidopepsin B
Scytalidocarboxyl peptidase B, also known as Scytalidoglutamic peptidase and Scytalidopepsin B is a proteolytic enzyme. It was previously thought to be an aspartic protease, but determination of its molecular structure showed it to belong a novel group of proteases, glutamic protease.
The protease has a unique structure and a novel catalytic dyad in its active site. The active-site residues, glutamic acid and glutamine, was used to coin the name of the family of proteases, eqolisins, to which Scytalidoglutamic peptidase B belongs.
This enzyme catalyses the following chemical reaction
This endopeptidase is isolated from Scytalidium lignicolum. It is an acid protease, and is most active at pH 2.0 when casein is used as substrate. Eqolosins prefer bulky amino acid residues at the P1 site and small amino acid residues at the P1′ site. The substrate specificity of scytalidoglutamic peptidase is unique, particularly in the substrate preferences at the P3, P1′ and P3′ positions.
