Dear Emma,

Attached please find an article describes a sort of metabolism within the outer metochondrial membrane. I have copied the relevant paragraph for quick view:

An alternative process is now thought to be more commonly involved in the permeabilization of the outer mitochondrial membrane and release of apoptogenic proteins. This involves pore formation by pro-apoptotic members of the Bcl-2 family of proteins in the outer membrane [3] and [25]. The full details of this process are not yet elucidated but translocation of the proteins, Bim and Bax, from the cytosol to the mitochondrial membrane is commonly involved. Translocation of both proteins develops in the initial 4 h following 1 h of ischemia in rats and mice [83]. The expression of these proteins is also increased at these times [81] and [83]. Translocation of Bax and Bim to the mitochondria following ischemia apparently involves activation of c-Jun N-terminal kinase (JNK). Pretreatment of mice with a JNK inhibitor immediately prior to 1 h of ischemia in mice decreases movement of these proteins to the mitochondria and decreases the number of cells exhibiting features of apoptosis, predominantly in penumbral regions [83] and [105]. Movement of the Bcl-2 family protein, Bad, from the cytosol to the mitochondria can also contribute to mitochondrial membrane permeabilization under some circumstances. Translocation of this protein has also been detected following temporary ischemia [106] (but see also [83]).

Hoping this will be helpful,

Rafik

The review (http://www.ncbi.nlm.nih.gov/pubmed/10816120) is quite old but gives a nice overview on the functions of the outer mitochondrial membrane. Therefore it could be interesting for you.

Cheers, Christian