An extremely complex, naturally occurring molecule known as a protein is made up of amino acid residues connected by peptide bonds.
All living things contain proteins, which are the building blocks of numerous vital biological substances like enzymes, hormones, and antibodies.
Proteins as enzymes:
Proteins are called enzymes to increase the likelihood that a biochemical reaction will proceed by reducing the reaction's activation energy.
Amylase is an example of protein.
Proteins as hormones:
Protein hormones interact with cell surface receptors in a quick-moving chain of events that leads to hormone activity.
Example insulin is produced by the pancreas.
Proteins as antibodies:
B cells, which are a component of the body's immune system, produce antibodies, which are proteins that each B cell uniquely makes and that each B cell recognizes an epitope on the antigen.