Holoproteins are proteins that consist entirely of amino acids, which are the building blocks of proteins. They do not contain any non-protein components, making them pure proteins. Holoproteins play essential roles in various biological functions, including catalyzing reactions, transporting molecules, and providing structural support in cells. Examples of holoproteins include enzymes, antibodies, and hemoglobin. These proteins are crucial for maintaining the body's functions and are found in many foods, contributing to our nutritional needs. Understanding holoproteins helps in studying their roles in health and disease.