which amino acid is LEAST likely to participate in acid base

which amino acid is LEAST likely to participate in acid base catalysis:

A) lysine

b)valine

c) aspartate

d) histidine

Solution

Amino acids, by virtue of charged amino and carboxyl groups can behave as either acids or bases. These charged molecules may often be present in enzymes. The residues therefore contribute in general acid and base catalysis at different points in a single enzyme cycle.

One of the characteristic of amino acid that is able to participate in acid- base catalyses is the presence of either a positive charge or a negative charge. The positive charge may be conferred by a Amino group (NH₃⁺), and the negative charge may be conferred by a carboxyl group (COO^-).

Let us analyse each of the give amino acids -

Lysine and Histidine are positively charged

Aspartate is negatively charged.

Valine is the only uncharged and non-polar amino acid. Therefore, it will not take part in acid-base catalysis.

The correct answer is therefore Option B-Valine.