Other than disulfide bridges, the leading forces holding proteins together and making it possible for binding to other compounds are noncovalent interactions. Covalent bonds are encountered mostly involving proteins and many coenzymes. The noncovalent interactions are mainly ionic bonds, hydrogen bonds, and “hydrophobic interactions.” The basis for “hydrophobic interactions” https://pasquali956958partscatalo59492.tinyblogging.com/Details-Fiction-and-Pasquali-Era-9-40-Parts-Catalog-53913089