Hydrolases;
Acting on peptide bonds (peptidases);
Serine endopeptidases
Reaction(IUBMB)
Selective cleavage after Arg223 in complement component C2 (-Ser-Leu-Gly-Arg!Lys-Ile-Gln-Ile) and after Arg76 in complement component C4 (-Gly-Leu-Gln-Arg!Ala-Leu-Glu-Ile)
Comment
Mannan-binding lectin (MBL) recognizes patterns of neutral carbohydrates, such as mannose and N-acetylglucosamine, on a wide range of microbial surfaces and is able to initiate activation of the lectin pathway of complement [7]. This enzyme displays C_overbar_1s_-like esterolytic activity (cf. EC 3.4.21.42, complement subcomponent C_overbar_1s_). It also cleaves C4 and C2 with efficiencies that are relatively higher than those of EC 3.4.21.42 [3]. Belongs in peptidase family S1A.
Harmat V, Gal P, Kardos J, Szilagyi K, Ambrus G, Vegh B, Naray-Szabo G, Zavodszky P.
Title
The structure of MBL-associated serine protease-2 reveals that identical substrate specificities of C1s and MASP-2 are realized through different sets of enzyme-substrate interactions.
The two major oligomeric forms of human mannan-binding lectin: chemical characterization, carbohydrate-binding properties, and interaction with MBL-associated serine proteases.