Amino Acids and Peptide Bonds

By Mihir Kapse | 2 October 2024

The word ‘proteins’ pops up everywhere in many different conversations. Sometimes it is about food diet and a few times it might be about biomolecules, diseases, or genetic material. These all have proteins as a major component. Proteins are nothing but bio-polymers of a type of amino acid called alpha-amino acids.

Fundamentally, amino acids are organic compounds that have both functional groups: amino and carboxyl. Depending on the relative position of these two functional groups, amino acids are classified into various types. All biological systems mainly consist of alpha-amino acids. They are of extreme importance to all biological life.

In 1806, French chemists Vauquelin and Robiquet successfully isolated Asparagine, the first amino acid to be discovered. Later on in 1810, another amino acid Cystine was discovered. Subsequently, more and more amino acids were discovered. Currently, we know that over 500 amino acids exist in nature.

For us, there are majorly two types of amino acids: essential and non-essential amino acids. Essential are the ones that our body cannot synthesise on its own and so we rely on diet. On the other hand, non-essential amino acids are the ones that our body can synthesize. Amino acids are found everywhere in our body. Enzymes, hormones, protein synthesis, neurotransmitters, etc all require amino acids.

Beyond their role as residues in protein, amino acids participate in other biological processes such as neurotransmitter transport and biosynthesis. Amino acids are also added to animal feed to fulfil animal’s requirements for their essential amino acids. Because of their chelating ability, they are sometimes used in fertilizers to facilitate the delivery of minerals to plants.

Proteins, as said above, are polymers of amino acids. These amino acids are connected to each other by peptide bonds. Chemically, peptide bonds are an amide linkage formed between the carboxyl and amino groups of two amino acids.

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During the process of translation, peptide bonds are formed leading to the synthesis of protein. Peptide bonds also decide the overall structure of proteins. It also has broad applications in biotechnology and medicine (for example, peptide-based drugs), as peptide bonds can be synthetically created.

References:

  1. Muller, P.. Glossary of terms used in physical organic chemistry. Pure and Applied Chemistry. 1994
  2. Nelson DL, Cox MM. Principles of Biochemistry (4th ed.). New York: W. H. Freeman. 2005
  3. Flissi, Areski; Ricart, Emma; Campart, Clémentine; Chevalier, Mickael; Dufresne, Yoann; Michalik, Juraj; Jacques, Philippe; Flahaut, Christophe; Lisacek, Frédérique; Leclère, Valérie; Pupin, Maude. Norine: update of the nonribosomal peptide resource. Nucleic Acids Research. 2020
  4. Vauquelin LN, Robiquet PJ. The discovery of a new plant principle in Asparagus sativus. Annales de Chimie. 1806
  5. Wollaston WH. On cystic oxide, a new species of urinary calculus. Philosophical Transactions of the Royal Society. 1810
  6. Leuchtenberger W, Huthmacher K, Drauz K. "Biotechnological production of amino acids and derivatives: current status and prospects". Applied Microbiology and Biotechnology. November 2005
  7. Ashmead HD. Foliar Feeding of Plants with Amino Acid Chelates. Park Ridge: Noyes Publications. 1986

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