Q13.21P - Chemistry: Molecular Nature Of Matter And Change

Question

Question: In what way do proteins embedded in a membrane differ structurally from soluble proteins?

Step-by-Step Solution

Answer

Answer

 

Proteins embedded in a membrane differ in a fundamental way from soluble proteins. Soluble proteins are hydrophilic in nature, containing outer hydrophilic amino acids which interact with water while membrane proteins hydrophobically contain a non-polar hydrophobic region embedded in the lipid bilayer.

 

Step 1: Site of proteins

 

Soluble proteins are present in the cytoplasm, mitochondria, and nucleus (hydrophilic environment) while membrane proteins are found embedded in a lipid bilayer (hydrophobic environment). Because of different environments, both these proteins are structurally different.

 

Step 2: Structure of soluble proteins

 

Soluble proteins are water-soluble in nature because of hydrophilicity. Their outer part contains hydrophilic amino acids (polar part) which interact with water and hydrophobic amino acids are deep buried in the inner part of the protein, away from water.

Step 3: Structure of membrane proteins

Membrane proteins are lipid-soluble in nature because of hydrophobicity. The outer part contains hydrophobic amino acids (non-polar part) which lie within the lipid bilayer, interacting with it by dispersion forces and the hydrophilic polar part is located away from the lipid bilayer interacting with the water molecules.