What chemical elements form a protein molecule?

Proteins are made up of five chemical elements. Proteins are half carbon. Oxygen is about 25%. Nitrogen occupies up to 18% of the protein composition. Hydrogen takes up about 7% of proteins, and sulfur can take up to 2.5%. In addition to these five chemical elements, proteins can also include some other molecules. For example, phosphorus or iron. It all depends on the type of protein, since they are different in nature and can be formed by different amino acids. By the number of amino acids, proteins have their own classification.