Table 1.
Molecule and environment | Diffusion coefficient (μm2/s) | Time to traverse 20 μm (Brownian diffusion; seconds)# | Reference(s)* |
---|---|---|---|
Small molecule (fluorescein) in water | 430 | 0.2 | Culbertson et al., 2002 |
Protein (GFP) in water | 90 | >1 | Swaminathan et al., 1997 |
Small molecule (fluorescein) in cytoplasm | 30 | >3 | Luby-Phelps et al., 1986 |
Protein (GFP) in cytoplasm (CHO cell) | 30 | >3 | Swaminathan et al., 1997 |
Protein (GFP) in cytoplasm (bacterium) | 8 | 12.5 | Elowitz et al., 1999 |
Lipid tracer in fluid model membranes (DOPC; free-standing membrane) | 5–15 | 1.6–20 | Ramadurai et al., 2009 |
Lipid tracer in membrane blebs (cell membrane without cortical actin) | 1–10 | 10–100 | Tank et al., 1982 |
Lipid-anchored protein@ in fluid model membrane | 5 | 20 | Kahya et al., 2005 |
Integral membrane protein in fluid model membrane | 2–5 | 20–50 | Ramadurai et al., 2009 |
Lipid tracer in cell membrane | 0.5–4 | 25–200 | Tank et al., 1982 |
Lipid-anchored protein@ in cell membrane | 0.1–1 | 100–1000 | Zhang et al., 1991 |
Lipid-anchored protein@ in cell membrane blebs (without CA skeleton) | 0.3–0.6 | 170–330 | Zhang et al., 1991 |
Integral membrane protein in cell membrane blebs (CA skeleton-free) | 0.01–0.5 | 200–10000 | Tank et al., 1982 |
Integral membrane protein in cell membrane$ | 0.001–0.1 | 1000–100000 | Tank et al., 1982 |
The time to traverse the distance x was calculated as τ ≈ x2/4D, where D denotes the diffusion coefficient.
Some membrane proteins can exhibit only small mobile fraction or have even slower D.
GPI-anchored proteins were tested in cited works.
Original articles listed only.