Protein or the physical region of the protein that participates in chemical catalysis. In solution proteins also undergo variation in structure through thermal vibration and the collision with other molecules. Proteins can be informally divided into three main classes, which correlate with typical tertiary structures: globular proteins, fibrous proteins, and membrane proteins. Almost all globular proteins are soluble and many are enzymes. Fibrous proteins are often structural, such as collagen, the major component of connective tissue, or keratin, the protein component of hair and nails. Membrane proteins often serve as receptors or provide channels for polar or charged molecules to pass
Artificial nails polymer with "liquid monomer", usually ethyl methacrylate mixed with some inhibitor, forms a malleable bead. This mixture begins to cure immediately, continuing until completely solid in minutes. Another common material is acrylic gel, which contains photoinitiators that prevent its curing until exposed to either ultraviolet light within a certain wavelength. Some new techniques, too, have been invented, attempting to make obsolete the two outlined above. Dipping, for instance, involves painting nails with special primer and base coats, then repeatedly painting the nail with a clear coat and submerging it in powder. Nail products are available in a variety of colors