Amino Acids, Proteins and Porphyrins
Which one of the following amino acids is most likely to be found in the transmembrane region of a protein?
Cell membrane is made up of lipid bilayer.
a. The unique characteristic of this layer is that it has its hydrophobic ends in the center of the membrane while its hydrophilic ends lie on the outer surface of the membrane.
b. So if a protein forms a part of the membrane it has to be amphipathic i.e., the hydrophilic amino acids of the protein should protrude at the inside and outside faces of the membrane while hydrophobic amino acids of the protein should lie in the center (or the transmembrane region).
So, Hydrophobic amino acids → Present in transmembrane region.
Hydrophilic amino acids →Present on outer surface of membrane
Leucine is a hydrophobic amino acid so it lies in the transmembrane region.
Other hydrophobic amino acids are Isoleucine