the translocase of the outer membrane (tom) is a complex of proteins found in the outer mitochondrial membrane of the mitochondria. it allows movement of proteins through this barrier and into the intermembrane space of the mitochondrion. most of the proteins needed for mitochondrial function are encoded by the nucleus of the cell. the outer membrane of the mitochondrion is impermeable to large molecules greater than 5000 daltons. the tom works in conjunction with the translocase of the inner membrane (tim) to translocate proteins into the mitochondrion. many of the proteins in the tom complex, such as tomm22, were first identified in "neurospora crassa" and "saccharomyces cerevisiae".