When red-blood cells are treated extensively with protease most membrane proteins are broken down into small peptides.However,some proteins are very resistant to this treatment.If cleavage by protease is the only type of reaction that occurs in this treatment,how is this explained?
A)They are lipid-anchored membrane proteins.
B)They are peripheral proteins.
C)They contain at least 2 disulfide bonds.
D)They are integral (intrinsic)membrane proteins.

Question

Quizplus · Accepted Answer

Integral (intrinsic) membrane proteins are embedded within the hydrophobic core of the lipid bilayer and have transmembrane domains that are resistant to protease cleavage. Therefore, they are able to withstand extensive protease treatment while still maintaining their structure and function. Peripheral membrane proteins, on the other hand, are loosely attached to the outer surface of the lipid bilayer and are more susceptible to protease cleavage. Lipid-anchored membrane proteins contain covalently attached lipid groups that anchor them to the lipid bilayer and are also prone to protease cleavage. Disulfide bonds do offer some resistance to protease cleavage, but they alone would not be enough to confer substantial resistance to the treatment.

When Red-Blood Cells Are Treated Extensively with Protease Most Membrane