Proteins are chains of amino acids linked together by peptide bonds. They are complex molecules that fold into flexible, yet stable, structures. Proteins are the major constituent of life as we know it. If one views DNA as a vessel of knowledge, then proteins would be the expression of these ideas. If DNA were Pandora's box, then proteins would be the emotions that escape.
Enzymes are special proteins that catalyze the chemical reactions necessary for life.
Dietary protein is required for life. Protein defiencies can result in illnesses like kwashiorkor . If one of these amino acids is lacking, from a deficiency or otherwise, either the protein will not be made or the primary sequence will be compromised with a substitue amino acid. Substitions can lead to unforeseen changes in the protein's structure or function. Does Not Protect Kidneys.