Figure 2.

CCOX-II is a specific binding protein of rGIIA. This was confirmed when the CCOX-II was identified in the bound fraction of mitochondrial extract using the rGIIA-affinity media. (A) Porcine cerebral cortex P2d membranes were extracted with a detergent and the extract was chromatographed on an rGIIA-affinity column (rGIIA-CHS) and on a control column (EA-CHS). Proteins were eluted by lowering the pH from 7.4 to 5. The collected, unbound (BT) and bound fractions (E1 and E2) were analyzed with SDS-PAGE and the proteins were visualized via silver staining. Black boxes indicate the positions of excised bands. (B) The bands BP25 and BP20 were excised, and the proteins were reduced, alkylated and subjected to in-gel trypsin digestion. The resulting peptides were extracted from the gel and were analyzed by LC-MS/MS. Two tryptic peptides (red) from BP25 were identified as parts of the CCOX subunit II. No peptides could be identified in BP20.