Interaction between Serratia Protease and Human Plasma α2Macroglobulin

Abstract

Serratia protease (TSP) [EC 3.4.24] was bound stoichiometrically to α₂macroglobulin (α₂M), which was purified and crystallized from human plasma, but apo TSP was not bound. On formation of the TSP-α₂M complex the enzymatic activity of the bound TSP was affected with respect to substrates; K_m values of the bound TSP were unchanged but V_max values were reduced. α₂M was cleft at the mid-region of its subunits chains by TSP, which resulted in a conformational change of the α²M molecule with TSP.