Which amino acids have an acidic side chain?

Two amino acids have acidic side chains at neutral pH. These are aspartic acid or aspartate (Asp) and glutamic acid or glutamate (Glu). Their side chains have carboxylic acid groups whose pKa’s are low enough to lose protons, becoming negatively charged in the process.

Is the side chain of an amino acid acidic?

At a pH superior to their pK (Table 2), the carboxylic side chains lose an H+ ion (proton) and are negative charged. They are therefore acid. At a pH inferior to their pK, the aspartic acid and glutamic acid side chains are uncharged.

What is the side chain of an amino acid?

Each amino acid is bound to a unique chemical group at this position called its side chain. It is this side chain that makes each amino acid different, giving each amino acid a unique set of chemical properties. The side chain is often abbreviated as an R group and denoted with the letter R for short.

Do amino acids contain an R side chain?

Each of the 20 amino acids has a specific side chain, known as an R group, that is also attached to the α carbon. The R groups have a variety of shapes, sizes, charges, and reactivities. This allows amino acids to be grouped according to the chemical properties of their side chains.

What is the simplest amino acid?

The simplest amino acid is glycine, in which R is a hydrogen atom. In a number of amino acids, R represents straight or branched carbon chains.

What are the two groups of amino acids?

The naturally occurring amino acids have a common structure. Amino acids, as the name implies, have two functional groups, an amino group (–NH 2) and a carboxyl group (– COOH ). These groups are joined to a single (aliphatic) carbon.

What is the pH level of amino acids?

The isoelectric point (IP) is the pH at which the amino acid has an overall zero charge The isoelectric points (IP) of amino acids range from 2.8 to 10.8 Glycine, with an IP of 6.0 exist as a positively charged species at a pH below 6.0 pH = 6.0 pH< 6.0 .

What are protein side chains?

In proteins, which are composed of amino acid residues, the side chains are attached to the alpha-carbon atoms of the amide backbone. The side chain connected to the alpha-carbon is specific for each amino acid and is responsible for determining charge and polarity of the amino acid.