Metal content and subunit composition of bean and bovine cytochrome C oxidases
Cytochrome c oxidase (CcO) isolated from imbibed whole beans (Phaseolus vulgaris) and bovine hearts have been compared in terms of metal content, subunit composition, and dioxygen reduction site. Both preparations contain Zn and Mg as well as Cu and Fe, with similar Fe/Zn ratios (2.5). Both enzymes also contain multiple subunits of comparable molecular weights and exhibit sharp CO-IR specta for heme iron bound carbonyl species. Alkaline detergent treatment of the bovine enzyme (i.e. incubation with 1% Triton X-100, pH 9.5, followed by ion exchange chromatography) has been reported by others to remove subunit III with loss of H+ pumping activity in reconstituted proteoliposomes without loss of oxidase activity. However, the authors find the treatment does not alter subunit distribution as visualized by SDS-Urea PAGE or HPLC analysis and markedly reduces activity (90%). Metal atom ratios of the treated enzyme indicate a loss of Fe and Mg (Cu/Fe 2.33 +/- 0.24, Fe/Zn 1.64 +/- 0.34, Mg/Zn 0.76 +/- 0.22) relative to native CcO (Cu/Fe 1.23 +/-0.06, Fe/Zn 2.47 +/- 0.14, Mg/Zn 0.94 +/- 0.05). These data provide evidence for similarity between plant and mammalian oxidases and lend further support for vital roles of Zn, Mg, Fe, and Cu in CcO.
- Research Organization:
- Colorado State Univ., Fort Collins
- OSTI ID:
- 5254127
- Report Number(s):
- CONF-8606151-
- Journal Information:
- Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Vol. 45:6; Conference: 76. annual meeting of the Federation of American Society for Experimental Biology, Washington, DC, USA, 8 Jun 1986
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
OXIDOREDUCTASES
CHEMICAL COMPOSITION
BEANS
CATTLE
COPPER
CYTOCHROMES
ENZYME ACTIVITY
HEART
ION EXCHANGE CHROMATOGRAPHY
IRON
MAGNESIUM
MOLECULAR WEIGHT
PHASEOLUS
QUANTITY RATIO
ZINC
ALKALINE EARTH METALS
ANIMALS
BACTERIA
BODY
CARDIOVASCULAR SYSTEM
CHROMATOGRAPHY
DOMESTIC ANIMALS
ELEMENTS
ENZYMES
FOOD
LEGUMINOSAE
MAMMALS
METALS
MICROORGANISMS
ORGANIC COMPOUNDS
ORGANS
PIGMENTS
PLANTS
PROTEINS
RHIZOBIUM
RUMINANTS
SEPARATION PROCESSES
TRANSITION ELEMENTS
VEGETABLES
VERTEBRATES
550200* - Biochemistry