Question

I have a mixture of muscle proteins and glycogen. When I heat the solution, the proteins form aggregates, whereas the glycogen does not. Consider this situation, what conclusion, summary or hypothesis can you get?

Answer 1

The stability of a protein depends upon its tertiary and quaternary structures. A protein is folded into its native structure so that it has optimum contacts with the surrounding environment. When a protein molecule is dissolved in water, it maintains its stability by burying its hydrophobic amino acids inside the core and only hydrophilic amino acids are exposed. If we heat this solution, all the molecular associations will be disrupted leading to the unfolding of the protein. This unfolded protein forms insoluble coagulants.

However, glycogen is a polysaccharide composed of glucose molecules. Glucose is a hydrophilic molecule. The solubility of a solute in water increases with increases in temperature. Hence, glycogen does not precipitate out of the solution when heated.