Peptide Bond: Definition, Formation & Structure
Peptide bonds are the key linkages found in proteins. These bonds connect amino acids and provide one of the key foundations for protein structure. This article discusses peptide bonds, their formation, and their structure.
We also recommend watching Lewis Structures: Single, Double & Triple Bonds and Covalent Bonds: Predicting Bond Polarity and Ionic Character
Proteins are a class of macromolecules (large molecules) that are important in biological systems. Almost all of the components of an organism will contain one or more types of protein in order to function properly. Your hair, for example, contains keratin, which is a protein used to make each strand. Your skin, likewise, contains proteins such as collagen, which is used to allow stretching. In addition to this, many of the biological systems require proteins for biochemical processes. For example, in muscle, proteins are responsible for contraction and energy usage. In the stomach, protein enzymes , which are biological catalysts, speed up the process of food digestion. In essence, proteins are vital for survival.
Proteins are formed from amino acids, which are the building blocks for this particular macromolecule. Amino acids are joined together in a process known as polymerization, which is where large molecules are produced by combining smaller units. Polymerization is achieved by the formation of special bonds known as peptide bonds.
Key Components of Amino Acids
Every amino acid will have two key chemical groups: an amine group and a carboxyl group. Amine groups are composed of one nitrogen and two hydrogen atoms (-NH2). Carboxyl groups contain one carbon double bonded to an oxygen and single bonded to a hydroxyl (-OH) group. These two groups form the foundation of for peptide bonds, and are seen in the generic amino acid shown below.
Peptide Bond Formation
Peptide bonds form through a process known as dehydration synthesis. In dehydration synthesis, a chemical bond is formed through the loss of a water molecule. When two amino acids bond, the nitrogen of one amine group will bond to the carbon of the other amino acids carboxyl group. In the process, the amine group will lose a hydrogen atom, while the carboxyl group will lose an -OH. This process is endergonic, which means that energy is required to make this bond and will be stored here until the bond is broken.
Proteins are formed from amino acids, and the bond that connects them is called a peptide bond. Peptide bonds are formed between the amine group of one amino acid and the carboxyl group of another. In the process, water is removed and the resulting bond stores energy until broken.
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