Alternative Name: Tripeptidyl peptidase II
Source/Host: Isolated from human erythrocytes.
Long Term Storage: +4°C
Miscellaneous/General: TPPII plays a critical role in cleaving proteasomal-expressed peptides into tripeptides that can be further degraded by dipeptidyl peptidase II (DPPII) and aminopeptidases. There are also more specific roles for TPPII, such as its role in major histocompatibility complex (MHC) class I antigen processing. Native TPPII is a high molecular mass homomeric protein where the subunit (138 kDa) forms a large cylinder-like and well-organized complex (Mr>106), approximately 17 nm in diameter and 50 nm in length. The enzyme has a catalytic domain of the subtilisin-type, but in comparison with other subtilases, it has a 200 amino-acid insertion between the Asp and His of the catalytic triad.