Protein Structure: Effect of pH and Temperature

What stabilizes the 3D conformation of proteins?

Weak hydrogen bonds or interactions between R groups of amino acids.

What can break the weak bonds that stabilize protein structure?

Heat or changes in pH.

What is denaturation in proteins?

The permanent alteration of a protein's structure, often forming an insoluble precipitate.

How does heat affect protein structure?

It increases kinetic energy, causing vibrations that break weak bonds or other interactions

What will the breaking of these bonds result in?

The polypeptide chain unfolding causing the overall 3D shape to change

What happens to protein attractions when pH is changed?

Increased pH (alkali) or decreased pH (acid) alters attractions between side chains

What are these attractions important for?

The 3D shape of a protein

What does this disruption compromise?

The functionality of the protein

Denaturation of albumen in egg white by heat

What happens when an egg is fried?

The added heat leads to the breaking of hydrogen bonds and cross-linkage between sulfur containing R-groups of amino acids in the polypeptide

What does the breakage of these bonds form?

Disulfide bridges

What is trapped inside this structure?

Water making it form an insoluble soft gel