7 Differences between Intrinsic and Extrinsic Membrane Proteins

Feb 16, 2023 · 2 min read ·

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Cell membrane or plasma membrane is thin, outermost boundary in animal cell as animal cell lacks cell wall. In plant cell it is seen inner to cell wall. Each cell is surrounded by a plasma membrane. It is made up of lipids, proteins and small amount of carbohydrates. There are two types of proteins on the plasma membrane based on its location.

1) Intrinsic or Integral or internal proteins 2) Extrinsic, peripheral or external proteins

Intrinsic vs Extrinsic Proteins

Intrinsic and Extrinsic Membrane Proteins

Extrinsic Proteins or Peripheral protein	Intrinsic Proteins or Integral proteins
They occur on the surface of the plasma membrane.	They are embedded in the plasma membrane either partially or completely sometimes span the membrane many times.
External proteins are hardly 30% of the total membrane proteins.	They constitute 70% of the total membrane proteins.
They are more hydrophilic and less hydrophobic	They are more hydrophobic and less hydrophilic towards the
They are loosely bounded to the lipid bilayer by weak non-covalent molecular attractions (ionic, hydrogen, and/or Van der Waals bonds) without much contact with the hydrophobic core.	They are embedded in the lipid bilayer firmly having direct contact with the hydrophobic core. These proteins contain non-polar sequences that are hydrophobically bonded to the lipid bilayer.
Easily removed with mild treatment such as shaking with a dilute salt solution.	Difficult to separate from the cell membranes and removal of such proteins using detergents from the membrane often destroys the membrane structure.
They function as receptors, antigens, recognition centres etc.	They function as carrier proteins, enzymes, transport channels (translocases), permeases.
Example: Erythrocyte spectrin, mitochondrial cytochrome c in Electron transport chain	Example: Glycophorin, Rhodopsin, NADH dehydrogenase in ETC

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