Increased amount of a mitochondria-associated 21 x 10(3) dalton protein in human gastrointestinal tumors.

Differences in the structure and number of mitochondria in tumor cells were found. Using isoelectrofocusing two-dimensional polyacrylamide gel electrophoresis which allows detection of alterations in the protein pattern of tumor mitochondria, we studied both quantitative and qualitative changes in the mitochondrial protein pattern of human gastrointestinal tumors and corresponding normal matrix tissues. One low molecular protein spot was found to be quantitatively changed in the tumors. The approximate molecular weight was 21 x 10(3) daltons and the pI value 5.7.