Question

What functional groups are found in proteins?

Answer 1

The one functional group that is found in all proteins is the amide group or peptide bond.

Explanation:

Peptide bond
(from chemwiki.ucdavis.edu)

In addition, proteins may contain a wide range of functional groups in the sidechains of the amino acid residues:

• alcoholic `"OH"` groups in serine and threonine
• phenolic `"OH"` groups in tyrosine
• `"SH"` groups in cysteine
• `"COO"` groups in aspartic and glutamic acids
• `"NH"_2` groups in lysine
• `"CONH""2` groups in asparagine and glutamine

Amino Acids
(from amit1b.wordpress.com)