Many proteins that are soluble in water have hydrophobic int

Many proteins that are soluble in water have hydrophobic “interiors”, but have an outside layer of hydrophilic amino acids. Why is this structure both fairly stable, and soluble in water?

Solution

Proteins are build up of amino acids. All amino acids have a similar backbone structure, but differ in their side chains. These side chains have different properties, some are hydrophobic (not water soluble) whereas others are hydrophilic(water soluble).

To form a functional protein, the amino acid chain is folded in a way that the hydrophobic parts end up on the inside and the hydrophilic parts on the outside.

This way a stable, water soluble protein is formed.