What is Globular protein?
[[Image:1GZX Haemoglobin.png|thumb|300px|3-dimensional structure of [[hemoglobin]], a globular protein.]] A '''globular protein''' is one of a common type of [[protein]]. They are one of three types of protein. The others are [[fibre|fibrous]] and [[membrane]] proteins. Their structure is a result of [[protein folding]]. They are made of [[polypeptide]] chains folded into a compact sphere shape. They are soluble in water because of the hydrophilic ('water-loving') side chains that project from the outside of the molecules. They play an important role in metabolic reactions. Unlike proteins which only have a structural function, globular proteins can act as: *[[Enzyme]]s, by [[catalysis|catalyzing]] organic reactions taking place in the [[organism]] in mild conditions and with a great specificity. Different [[esterase]]s fulfill this role. *[[Hormone|Messengers]], by transmitting messages to regulate biological processes. This function is done by [[hormone]]s, i.e. [[insulin]] etc. *[[Membrane transport protein|Transporters]] of other molecules through [[cell membrane|membrane]]s * Stocks of [[amino acid]]s. *Regulation of other molecules is also done by globular proteins rather than fibrous proteins. *Structural proteins, e.g., [[actin]] and [[tubulin]], which are globular and soluble as monomers, but polymerize to form long, stiff fibers. Globular proteins include [[myoglobin]] and [[hemoglobin]]. == Globulins == '''Globulins''' are all globular proteins except [[albumin]]s. They have higher molecular weights than albumins. They are insoluble in pure water but [[solvation|dissolve]] in dilute salt solutions. Some globulins have important function as [[antibodies]], others are responsible for the transport of [[lipids]], [[iron]] or [[copper]] in the [[blood]]. [[Category:Proteins]] {{commonscat|Globular proteins}} {{clear}}