Question

If the amino acids alanine and glycine react to form a peptide bond, is there more than one reaction product? If so, what products?

Short answer

Yes, there are two reaction products: Ala-Gly and Gly-Ala.

Step-by-step solution

Understand peptide bond formation

A peptide bond is formed between the carboxyl group (-COOH) of one amino acid and the amino group (-NH2) of another amino acid through a dehydration synthesis reaction, releasing a molecule of water (H2O).

Identify the amino acids involved

The amino acids involved in this reaction are alanine and glycine. Alanine has the structure H2N-CH(CH3)-COOH, and glycine has the structure H2N-CH2-COOH.

Consider all possible combinations

When alanine and glycine form a peptide bond, the bond can involve either: 1. The carboxyl group of alanine and the amino group of glycine, resulting in alanine-glycine (Ala-Gly). 2. The carboxyl group of glycine and the amino group of alanine, resulting in glycine-alanine (Gly-Ala).

List possible reaction products

The possible reaction products are: 1. Alanine-glycine (Ala-Gly) 2. Glycine-alanine (Gly-Ala)

Key concepts

amino acids

Amino acids are the building blocks of proteins. Each amino acid has a central carbon atom, which is bonded to four different groups: an amino group (-NH2), a carboxyl group (-COOH), a hydrogen atom, and a unique side chain (R group). The side chains vary among different amino acids and determine their properties. In this exercise, we are focusing on two specific amino acids: alanine and glycine.

dehydration synthesis

Dehydration synthesis is a chemical reaction that involves removing a molecule of water to form a new bond. In the context of peptide bond formation, the carboxyl group of one amino acid reacts with the amino group of another, releasing a molecule of water (H2O).
This reaction forms a covalent bond known as a peptide bond. It's essential for building proteins, where multiple amino acids are linked together through dehydration synthesis.

peptide bond

A peptide bond is a type of covalent bond that connects amino acids in a protein. It forms between the carboxyl group of one amino acid and the amino group of another through a dehydration synthesis reaction. This bond is crucial as it links the amino acids into a polypeptide chain, which later folds into a functional protein.
The formation of a peptide bond results in the creation of a dipeptide and the release of a water molecule.

reaction products

When alanine and glycine form a peptide bond, there are two possible reaction products:

• Alanine-glycine (Ala-Gly)
• Glycine-alanine (Gly-Ala)

In both cases, the formation of the peptide bond involves the release of a water molecule. The difference lies in which amino acid's carboxyl group and which one's amino group participate in the reaction. Both products are dipeptides, but formed in different sequences.

alanine

Alanine is an amino acid with the structure H2N-CH(CH3)-COOH. It has a methyl group (CH3) as its side chain. Alanine is classified as a non-polar, aliphatic amino acid and is often abbreviated as 'Ala' in protein structure descriptions. It is essential in protein metabolism and plays a role in glucose-alanine cycle.

glycine

Glycine is the simplest amino acid with the structure H2N-CH2-COOH. Its side chain is just a hydrogen atom, making it unique among amino acids. Glycine is categorized as a non-polar and uncharged amino acid. It is often abbreviated as 'Gly'. Glycine is important for the synthesis of proteins and also functions as a neurotransmitter in the central nervous system.