Cell Language Theory, The: Connecting Mind And Matter

142 The Cell Language Theory: Connecting Mind and Matter

b2861 The Cell Language Theory: Connecting Mind and Matter “6x9”

Figure 3.38 Kinetics of pH gradient, membrane potential (∆y), and spectral shift of

ferric cytochrome c oxidase from rat liver mitochondria. The membrane potential was

generated across the mitochondrial inner membrane by adding the ionophore valinomycin

(which binds K+ and carries it across the hydrophobic membrane) to the K+-loaded mito-

chondria, thus inducing a K+ ion efflux from mitochondria making the matrix space

electrically negative relative to the intermembrane space. The pH of the extra-mitochondrial

space was measured with neutral red absorbance change at 540–581 nm, the electrical

potential with safranine absorbance change measured at 509–542 nm, and the conforma-

tional state of the cytochrome c oxidase by differential absorbance of aa 3 at 436–418 nm.

Reproduced from [216]. CcO = Cytochrome c oxidase.

pH

∆ψ

Spectral shift of CcO

of the heme aa 3 of cytochrome c oxidase in rat mitochondria simultane-

ously, by adding valinomycin (the K+ ionophore) to mitochondrial suspen-

sion which caused the efflux of K+ from the mitochondrial matrix making

it electrically negative relative to the extra-mitochondrial space. The

results are shown in Figure 3.38 which can be summarized as follows:

(1) The extra-mitochondrial pH increased slowly and continuously with

a t½ of about 1.5 min.

(2) The membrane potential measured as the safranine optical signal rose

rapidly (reaching a maximal value in about 30 s) due to the valinomy-

cin-induced efflux of K+ and decayed slowly with a t½ of 5–6 min,

probably due to the slow equilibration of lipid-soluble ions across the

mitochondrial inner-membrane driven by the K+-ion gradient.

b2861_Ch-03.indd 142 17-10-2017 11:46:53 AM