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The 35 kDa DCCD-binding protein from pig heart mitochondria is the mitochondrial porin

1985; Elsevier BV; Volume: 813; Issue: 2 Linguagem: Inglês

10.1016/0005-2736(85)90238-x

1879-2642

Vito De Pinto, Massimo Tommasino, Roland Benz, Ferdinando Palmieri,

Metabolomics and Mass Spectrometry Studies

The protein which can be labelled by low concentrations of dicyclohexylcarbodiimide in the Mr region of 30000–35000 has been purified from pig heart mitochondria with a high yield and as a single band of apparent Mr 35000 in dodecyl sulphate-containing gels. The protein is not identical with the phosphate carrier as suggested before, since the two proteins behave differently during isolation. Incorporation of the isolated 35 kDa dicyclohexylcarbodiimide-binding protein into lipid bilayer membranes causes an increase of the membrane conductance in definite steps, due to the formation of pores. The specific pore-forming activity increases during the purification procedure. The single pore conductance is about 4.0 nS, suggesting a diameter of 1.7 nm of the open pore. The pore conductance is dependent on the voltage across the membrane. Anion permeability of the pore is higher than cation permeability. These properties are similar to those described for isolated mitochondrial and bacterial porins. It is concluded that the 35 kDa dicyclohexylcarbodiimide-binding protein from pig heart mitochondria is identical with porin from outer mitochondrial membrane.