BIOMOLECULES AND ENZYMES

Detailed explanation-1: -Complete answer: The most basic amino acid is Histidine. Glutamine and glycine aren’t basic amino acids. Only Arginine and Histidine are basic amino acids even out of these two, histidine is weakly charged under physiological ph.

Detailed explanation-2: -Histidine is classified as a basic amino acid because one of the N atoms in its five-membered ring is readily protonated by acid.

Detailed explanation-3: -There are three amino acids that have basic side chains at neutral pH. These are arginine (Arg), lysine (Lys), and histidine (His). Their side chains contain nitrogen and resemble ammonia, which is a base.

Detailed explanation-4: -The higher the pKa of the conjugate acid, the more tightly the proton is held, and so the more basic the nitrogen atom. Arginine is by far the most basic and histidine is the least basic.

Detailed explanation-5: -Lysine has two amine groups, which makes it overall basic because of the second isolated amine group (−(CH2)4NH2). Histidine, on the other hand, contains imidazole group, which is also basic. (see the chart), thus, lysine is considered to be more basic than histidine in physiological conditions.