Nature Biotechnology pp 281 - 286

Researchers have completed the most comprehensive attempt yet to catalog the protein content of human heart mitochondria--the molecular powerhouses that supply the energy for cardiac cells to beat. In the March issue of Nature Biotechnology, scientists at California-based company MitoKor, the University of Oregon's Institute for Molecular Biology, and the Buck Institute for Age Research, led by Steven W. Taylor, employ gel electrophoresis and mass spectrometry to separate and analyze a total of 615 proteins isolated from human heart mitochondria by density gradient centrifugation.

Their strategy succeeded in identifying more than 90% of the proteins and enzymes involved in respiration, the main function of mitochondria. Other ‘housekeeping' proteins, responsible for the day-to-day functioning of the mitochondrion, the relaying of signals arriving at the cell surface, and the exchange of molecules with the rest of the heart cell were also pinpointed. While the researchers correctly identified the function of many of the mitochondrial proteins, a proportion (approximately 20%) could not be assigned any known function or role.

This comprehensive catalog of mitochondrial proteins holds great promise for elucidating the molecular basis of human diseases that are linked with mitochondrial disorders.