Which type of proteins assists in proper protein folding?

Chaperons are proteins that assist in the folding of other proteins, ensuring they achieve their proper three-dimensional structures necessary for function. Protein folding is a critical process because the specific shape of a protein determines its function within the cell. If proteins do not fold correctly, they can become nonfunctional or even harmful to the cell, leading to diseases such as Alzheimer's or cystic fibrosis. Chaperons work by binding to nascent polypeptide chains during translation, preventing misfolding and aggregation, and providing an environment conducive to correct folding.

In contrast, enzymes catalyze biochemical reactions but do not directly assist in protein folding. Substrates are the reactants upon which enzymes act, meaning they are not involved in protein folding processes. Elongation factors are proteins that facilitate the elongation phase of protein synthesis during translation, providing assistance to the ribosome but not influencing the folding of proteins directly. This makes chaperons the correct choice for the role of assisting in proper protein folding.