6 a What is the main difference between an integral membrane

6. a) What is the main difference between an integral membrane protein and a peripheral membrane protein?
b) If you wanted to isolate a peripheral membrane protein from the plasma membrane of a cell, what treatment would you subject the cell to?
c) What treatment would you subject the cell to in order to isolate an integral membrane protein?
d) If you perform the treatment that you have listed in (c), would you expect to isolate only integral membrane proteins or both integral membrane proteins and peripheral membrane proteins? Why?

Solution

6

(a)

Peripheral membrane proteins do not interact with the hydrophobic core of the phospholipid bilayer.

- temporarily bound either to the lipid bilayer or to integral proteins by hydrophobic, electrostatic, and other non-covalent interactions.

example - cytochrome C in the electron transport chain.

Most integral proteins span the entire phospholipid bilayer.

Example: Transport proteins, ion channels