A chemical reaction in which water is used to break the bonds of certain substances. In biotechnology and living organisms, these substances are often polymers. In a hydrolysis reaction involving an ester link, such as that found between two amino acids in a protein, the products that result include one that receives the hydroxyl (OH) group from the water molecule, and another that becomes a carboxylic acid with the addition of the remaining proton (H+).
Hydrolysis reactions in living organisms are performed with the help of catalysis by a class of enzymes known as hydrolases. The biochemical reactions that break down polymers such as proteins (peptide bonds between amino acids), nucleotides, complex sugars and starch, and fats are catalyzed by this class of enzymes. Within this class, lipases, amylases and proteinases hydrolyze fats, sugars and proteins, respectively.
Cellulose-degrading bacteria and fungi play a special role in paper production and other everyday biotechnology applications, because they have enzymes (cellulases and esterases) that can break cellulose into polysaccharides (polymers of sugar molecules) or glucose, and break down stickies.