Diffusion coefficient of GFP (Green Fluorescent Protein) in mitochondrial matrix

Range 20 - 30 µm^2/sec
Organism Chinese hamster ovary (CHO)
Reference Verkman AS. Solute and macromolecule diffusion in cellular aqueous compartments. Trends Biochem Sci. 2002 Jan27(1):27-33 p.31 left column top paragraphPubMed ID11796221
Method Abstract: "Recent measurements of fluorescent probe diffusion using photobleaching, correlation microscopy and time-resolved anisotropy methods, have indicated unexpectedly high mobilities of small solutes and macromolecules." P.30 right column bottom paragraph: "Control studies showing slowed or abolished fluorescence recovery after paraformaldehyde fixation (Fig. 3b, right), or with increased spot size or bleach time, confirmed that the recovery represented authentic diffusion. The fluorescence recovery data were analyzed using a mathematical model of matrix diffusion. Mitochondria were modeled as long, continuously open cylinders with a specified orientational distribution (Fig. 3b, inset, top)."
Comments P.31 left column top paragraph: "Fluorescence recoveries were computed from analytical solutions to the diffusion equation. Predicted recovery curves for different diffusion coefficients are shown in Fig. 3b (left) along with experimental data. The fitted diffusion coefficient was 2–3 × 10−7 cm^2/s, only 3–4-fold less than that for GFP diffusion in water. The actual GFP diffusion coefficient is probably slightly higher because the mitochondria contain internal barriers called cristae (Fig. 3b, inset, bottom)."
Entered by Uri M
ID 116219