We also have hydrogen bonds and we have a type of Covalent bond known as a disulfide bond or a disulfide bridge. This is a covalent bond that is formed between two adjacent 15 amino acids. Now, the more disulfide bonds we have inside the alpha carotene, the stronger and the more rigid that molecule is that protein is. Now. What about globular proteins? Well, Globular proteins have a very, very wide range of functions.