Protein acts as buffer due to which propey
Most biomolecules are amphipathic; that is, they possess regions rich in charged or polar functional groups as well as regions with hydrophobic character. Proteins tend to fold with the R-groups of amino acids with hydrophobic side chains in the interior. Amino acids with charged or polar amino acid side chains. Ref: Harper's Illustrated Biochemistry, 30E (2015) Pg No 8.
Colloid
Basic
Acidic
Amphipathic (amphoteric in nature)
Structure and function of protein