And inside our body, we only have 20 different types of amino acids that constitute the different types of proteins. Now, the next question is, how exactly are these amino acids held together inside any given protein? So what is the type of bond that holds our amino acids together? Well, this bond is actually a special type of covalent bond known as a peptide bond or an AmiB. So let's begin by taking a look at the following reaction that basically describes the reaction that forms this peptide bond. So let's suppose we're on the reactant side, and on the reactant side, we have amino acid A and amino acid B.