Fig. 2.

Purification of outer mitochondrial membrane (OMM) and OMM-inner mitochondrial membrane (IMM) contacts from rat heart mitochondria. Mitochondria isolated from rat heart homogenates were subfractionated on a discontinuous sucrose gradient as the scheme shows at left (with sucrose concentrations shown as percent weight per volume). Protein concentration profile (bottom) and normalized (to the maximum, max) activities (top) of monoaminooxidase (MAO), an OMM resident, and succinate dehydrogenase (SDH), an IMM localized enzyme in the isolated subfractions, are shown. Data are means ± range from 2 independent preparations (each from 2 hearts).