Abstract
The role of zinc in beef heart cytochrome c oxidase has been studied by using x-ray absorption spectroscopy, zinc depletion and secondary structure predictions of subunits of beef heart cytochrome c oxidase. The stoichiometry of zinc in cytochrome oxidase has been determined in 35 different preparations and found to be one-half of copper (Cu:Zu = 2:1). Zinc is tightly bound to this enzyme and cannot be removed by dialysis against EDTA. However, zinc could be partially (up to 50%) depleted by treating the enzyme with either dipicolinic acid or by trypsin digestion. This partial depletion of zinc does not change the O2 uptake rate. X-ray absorption spectroscopy shows that the atom is in a distorted tetrahedral environment with mostly sulfur ligands. Since subunit VIa removed by the digestion removes about one-half the zinc, a possible binding site involves the two S sites present in that subunit with an appropriate folding in a structural role.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 12342-12345 |
| Number of pages | 4 |
| Journal | The Journal of biological chemistry |
| Volume | 263 |
| Issue number | 25 |
| State | Published - 1988 |
ASJC Scopus subject areas
- Biochemistry
- Molecular Biology
- Cell Biology