POSTMORTEM CHANGES IN SKELETAL-MUSCLE CONNECTIN (TITIN) AND ITS STRUCTURE

The splitting of the connectin (titin) molecule during meat conditioni ng and its primary structure were analyzed. Using immunofluorescence m icroscopy and immunoelectron microscopy, it was showed that the connec tin molecule split into beta-connectin and a 1,200 kDa-subfragment at a point 0.34 mu m apart from the Z-disc during meat conditioning. Diff erences in molecular weight and partial amino acid sequences of connec tin were determined for cattle, pig and chicken skeletal muscles. Resu lts of peptide mapping analysis differed according to animal species. Amino acid sequences deduced from partial nucleotide sequences of conn ectin also differed according to animal species at immunoglobulin-like (Ig) and fibronectin type 3(FN3) domains. In chicken, the molecular w eight of connectin from leg muscles differed from the value recorded i n pectoral muscles. It is suggested that meat texture and conditioning may be related to the splitting of the connectin molecule and its str ucture.