Biochemistry 4th Edition by Reginald Garrett, Charles Grisham

Exercise 5

Understanding diffusion of proteins in membranes
Protein lateral motion is much slower than that of lipids because proteins are larger than lipids. Also, some membrane proteins can diffuse freely through the membrane, whereas others are bound or anchored to other protein structures in the membrane. The diffusion constant for the membrane protein fibronectin is approximately 0.7 x 10 cm -12 cm 2 /sec, whereas that for rhodopsin is about 3 x 10 -9 cm 2 /sec.
a. Calculate the distance traversed by each of these proteins in 10 msec.
b. What could you surmise about the interactions of these proteins with other membrane components