Proteins consist of linear polymers

Proteins consist of linear polymers built from series of up to 20 different amino acids. All proteinogenic amino acids possess common structural features,including an alpha carbon to which an amino group,a carboxyl group, and a variable slide chain. These can form hydrogen bond swith many hydrogen atoms found in the molecule. The protein folds up to ensure that the maximum number of these hydrogen bonds is made. When the ambient pH increases, the amphoteric amino acidstend to stabilize and will lose H+at the COOH part of the molecule.This causes the overall shape of the membrane proteins to change with pH, and lead to functional disorder of cell membrane in turn.