Aspergillopepsin II

Aspergilloglutamic peptidase, also called aspergillopepsin II (EC 3.4.23.19, proctase A, Aspergillus niger acid proteinase A, Aspergillus niger var. macrosporus aspartic proteinase) is a proteolytic enzyme.^[1][2] The enzyme was previously thought be an aspartic protease, but it was later shown to be a glutamic protease with a catalytic Glu residue at the active site, and was therefore renamed aspergilloglutamic peptidase.^[3]

Aspergilloglutamic peptidase
Aspergilloglutamic peptidase dimer
Identifiers
EC no.	3.4.23.19
CAS no.	9025-49-4
Databases
IntEnz	IntEnz view
BRENDA	BRENDA entry
ExPASy	NiceZyme view
KEGG	KEGG entry
MetaCyc	metabolic pathway
PRIAM	profile
PDB structures	RCSB PDB PDBe PDBsum
Search PMC articles PubMed articles NCBI proteins

Determination of its molecular structure showed it to be a unique two-chain enzyme with a light chain and a heavy chain bound non-covalently with each other. The C-terminal region of the light chain of one molecule binds to the active site cleft of another molecule in the manner of a substrate.^[4]

This enzyme catalyses the following chemical reaction

Preferential cleavage in B chain of insulin: Asn³-Gln, Gly1³-Ala, Tyr²⁶-Thr

This enzyme is isolated from Aspergillus niger var. macrosporus.