... peroxidase labelling,density increasing of the Z -line, in particular at the edges of the structure, confirms the immunofluorescentstaining. On the other hand, labelling of the Z-bandregion by CP1 ... Consequently, the colocalization of calpain 1 and calpain 3 at N1- and N2 -line levels, the postmortem fractures at the N2 -line level, as well as the implication of titin in the bindingto calpain 3 [20] and ... calpain 1. We conclude that titin affords binding sites to cal-pain 1, which concentrates the protease in the regions restrained by the Z-band edge and the N1 -line as well as at the N2 -line level,...