Answer:
Amino acids with non-polar side chains.
Explanation:
The class of proteins that is unable to form hydrogen bonds with water are the amino acids with non- polar side chains. This class includes the amino acids
Alanine
Valine
Leucine
Isoleucine
Proline
Phenylalanine
Cysteine
Methionine
Tryptophan
These are the nine proteins which are considered to be strongly hydrophobic. All these amino acids are hydrophobic in nature due to their side chains. Glycine is not added to this list as it does not have a side chain.
