Hi,
Proteins (also known as polypeptides) are organic compounds made of amino acids arranged in a linear chain polymer and joined together by peptide bonds. They contain both amine and carboxyl functional groups as well as a varied side chain. Generally, the standard proteins will consist of the following elements:
Hydrogen
Carbon
Nitrogen
Oxygen
Sulfur, like those in amino acids L-Cysteine and L-Methionine
Occasionally, Selenium is found in proteins, such as those containing the non-standard amino acid L-Selenocysteine, an amino acid that is present in several protein enzymes like glutathione peroxidases, tetraiodothyronine 5' deiodinases, thioredoxin reductases, formate dehydrogenases, glycine reductases and some hydrogenases.
Additionally, depending on the protein, trace metals which act as cofactors may also appear in proteins, such as Iron, in the oxygen-binding site of hemoglobin, the main protein constituent of red blood cells.
Answered by
manu sharma
at
1:14 PM on May 17, 2012