Trypsin Is a Hydrophilic Protease and Therefore Is Unable to Cross

question 27

Essay

Trypsin is a hydrophilic protease and therefore is unable to cross the plasma membrane and enter a cell.However,it is capable of digesting the hydrophilic portions of membrane proteins.As a result of these properties,researchers investigating membrane proteins have treated cells with trypsin then separated the proteins by SDS-PAGE to gain insight into the orientation of particular proteins within the membrane.Describe an experiment using this information and the results you would expect with the following types of membrane-associated proteins.(Assume the proteins are single polypeptides.)
a.an integral membrane protein with the N-terminus exposed on the surface
b.an integral membrane protein with the C-terminus exposed on the surface
c.an integral membrane protein with three hydrophilic loops (only)exposed on the surface
d.a membrane-associated protein facing the cytoplasm
e.an imbedded membrane protein

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Definitions:

Gene Therapy

A medical treatment that involves altering the genes inside a person's cells to treat or prevent disease.

Cytoplasm

The gel-like substance inside the cell membrane containing enzymes, organelles, and the cytoskeleton, important for cellular functions.

Organelles

Functional structures within the cytoplasm of a cell.

Watery Environment

Describes an area or condition where there is a large presence of water; may refer to aquatic habitats or situations involving significant moisture.