Let's take a look at an example of biosynthesis to get a better understanding of this process. Proteins are a substance in the body made up of amino acid chains that join together by peptide bonds in a process called protein synthesis. There are 20 amino acids that make up the building blocks of proteins. Amino acids join together by peptide bonds to create chains of amino acids called polypeptide chains. The type of protein the body needs will dictate which amino acids are used in building these chains and how they are folded together to create a macromolecule.
In bacteria, the enzyme glutamate 5-kinase initiates the biosynthesis of proline by transferring a phosphate group from ATP onto glutamate. The next reaction is catalyzed by the enzyme pyrroline-5-carboxylate synthase (P5CS), which catalyzes the reduction of the ϒ-carboxyl group of L-glutamate 5-phosphate. This results in the formation of glutamate semialdehyde, which spontaneously cyclizes to pyrroline-5-carboxylate. Pyrroline-5-carboxylate is further reduced by the enzyme pyrroline-5-carboxylate reductase (P5CR) to yield a proline amino acid.