Aspergilloglutamic peptidase

Aspergilloglutamic peptidase (formerly called aspergillopepsin II) is a proteolytic enzyme produced by Aspergillus niger var. macrosporus. It is distinguished by a unique structure: two noncovalently bound polypeptide chains, featuring a catalytic dyad of glutamic acid and glutamine (not the aspartic residues found in classical aspartic proteases). It is an acid endopeptidase (MEROPS family G01.002, EC 3.4.23.19), involved in the breakdown of proteins with specific cleavage preferences. The enzyme is generated from a precursor through autocatalytic removal of its propeptide, which itself can act as a potent competitive inhibitor to the mature enzyme, also conferring thermal stabilization. Aspergilloglutamic peptidase is primarily of interest in fungal biology, protein engineering, and as a food enzyme. Unlike classical aspartic proteases, it is insensitive to pepstatin and similar inhibitors, reflecting its unique catalytic mechanism.

Other names

aspergillopepsin IIproctase AAspergillus niger acid proteinase AAspergillus niger var. macrosporus aspartic proteinase

Competitive inhibition by propeptide or its fragments (binds the enzyme at or near S1 site, disrupting substrate binding)\nEnzyme catalyzes proteolysis via a unique catalytic dyad (glutamic acid and glutamine residues)\nNot sensitive to common aspartic peptidase inhibitors such as pepstatin