which chemical elements are found in all proteins
Protein is composed of amino acids, which are in turn made up of mostly carbon, hydrogen, oxygen, and nitrogen. A few amino acids also contain sulfur: both Cysteine and Methionine. Thus, proteins containing these amino acids would be made up of very small amounts of sulfur, in addition to the more common elements listed above. The five chemical elements of protein are, 1.) sulfur 2.) carbon 3.) hydrogen 4.) oxygen 5.) nitrogen.