ENZYME

ENZYME entry: EC 3.4.23.32

Accepted Name

Scytalidopepsin B.

Alternative Name(s)

Scytalidium aspartic proteinase B.

Reaction catalysed

Hydrolysis of proteins with broad specificity, cleaving 24-Phe-|-Phe-25, but not 15-Leu-|-Tyr-16 and 25-Phe-|-Tyr-26 in the B chain of insulin

Comment(s)

Isolated from the imperfect fungus Scytalidium lignicolum.
A second endopeptidase from S.lignicolum (see scytalidopepsin A) that is insensitive to pepstatin and methyl 2-diazoacetamidohexanoate.
1,2-epoxy-3-(p-nitrophenoxy)propane reacts with Glu-53, which replaces one of the aspartic residues at the active center.
One of the smallest aspartic endopeptidases active as the monomer, with molecular weight 22 kDa.
Similarly inhibitor-resistant endopeptidases are found in the basidiomycetes Lentinus edodes and Ganoderma lucidum, and in Polyporus tulipiferae (a second endopeptidase distinct from polyporopepsin), but these are of typical aspartic endopeptidase size.
Belongs to peptidase family G1.

Cross-references

PROSITE

BRENDA

EC2PDB

ExplorEnz

PRIAM enzyme-specific profiles

KEGG Ligand Database for Enzyme Nomenclature