Mouse Legumain/Asparaginyl Endopeptidase Antibody

Legumain is a lysosomal cysteine protease found in all mouse tissues examined, but was particularly abundant in kidney and placenta (1). Legumain plays a pivotal role in the endosomal/lysosomal degradation system because the Legumain deficiency causes the accumulation of pro cathepsins B, H and L, another group of lysosomal cysteine proteases (2). Over-expression of Legumain in tumors is significant for invasion/metastasis (3). Also known as asparaginyl endopeptidase, it specifically cleaves peptide bonds with Asn at the P1 position. Nevertheless, it also cleaves peptide bonds with Asp at the P1 position. Auto-activation of pro Legumain involves both types of cleavage, which results in the removal of the pro peptides in both C- and N-termini (4). In addition, Legumain activates pro MMP‑2 and processes bacterial antigens for MHC class II presentation and pro thymosin alpha to thymosin alpha ₁ and thymosin alpha ₁₁, two acidic peptides with immunoregulatory properties (5‑7). Mouse Legumain is synthesized as a 435 amino acid precursor with a signal peptide (residues 1 to 17). The pro enzyme (residues 18 to 435) was expressed with an N-terminal His tag. The purified pro enzyme can be activated under the conditions as described above. Legumain activity can be inhibited by rmCystatin C and recombinant human cystatins C and E/M (R&D Systems, Catalog # 1238-PI, 1196-PI, and 1286-PI).