Plant mitochondrial F1-ATPase. The presence of oligomycin-sensitivity-conferring protein (OSCP).

Purified pea (Pisum sativum) cotyledon F1-ATPase contains six subunits rather than the five usually reported for F1-ATPases. The additional 26.5 kDa (delta) subunit is shown by immunoblotting and N-terminal amino acid sequencing to be similar to bovine oligomycin-sensitivity-conferring protein (OSCP). It is concluded that the delta subunit of plant mitochondrial F1-ATPase is the plant OSCP. This OSCP subunit occurs in all mono- and di-cotyledonous species of plants tested (maize, oats, peas, potatoes, sweet potatoes and turnips).