Respiratory Properties of Mitochondria Immobilized on Alkylsilylated Surfaces

Rat liver mitochondria are shown to adhere to the alkylsilylated glass beads in essentially a monolayer. The amount of mitochondria bound to the beads reaches a maximum where the length of the alkyl groups covalently linked to the beads exceeds eight carbons. Mitochondria immobilized on the beads and placed in a flow system exhibit normal: (a) respiratory control, (b) phosphate to oxygen ratio, (c) uncoupling by 2,4-dinitrophenol and carbonylcyanide p-trifluoromethoxyphenylhydrazone, and (d) inhibition by cyanide, azide, rotenone, oligomycin, and antimycin. Reversibility of the effects of 2,4-dinitrophenol, cyanide, and azide was rapid and complete. Inhibition by rotenone, oligomycin, and antimycin was essentially irreversible. Mitochondria have been maintained in a viable state on the beads at 27” for periods up to 4 hours. The use of immobilized organelles appears to offer a new technique for the study of membrane-bound particles whereby substances can be rapidly added and removed while monitoring the composition of solution flowing over the particles.