Answer to Question #46142 in Chemistry for deepu singh

Question

Why are the amino acids called alpha amino acids? The amino acids tyrosine and tryptophan have nonpolar side chains ; still these are placed in the uncharged polar group why ? Write the advantages of polar side chains in the amino acids.

Answer 1

Natural amino acids are called alpha amino acids, because the amino group is connected to the first carbon atom after carboxylic group. The amino acids tyrosine and tryptophan have polar andslightly polar side chains. They are placed in the uncharged group, because they are neutral. Side chains which have various functional groupssuch as acids, amides, alcohols, andamines will impart a more polarcharacter to the amino acid. The ranking of polarity will depend on the relative ranking of polarity for various functional groups. In addition, the number of carbon-hydrogens in the alkane or aromatic portion of the side chain should be considered along with the functional group.