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3-dimensional structure of hemoglobin, a globular protein.

Globular proteins, or spheroproteins are one of the two main protein classes, comprising globelike proteins that are more or less soluble in aqueous solutions (where they form colloidal solutions). This main characteristic helps distinguishing them from fibrous proteins (the other class), which are practically insoluble. Image File history File links Question_book-3. ... Image File history File links Size of this preview: 600 × 600 pixel Image in higher resolution (1600 × 1600 pixel, file size: 1,006 KB, MIME type: image/png)By Richard Wheeler (Zephyris) 2007. ... Image File history File links Size of this preview: 600 × 600 pixel Image in higher resolution (1600 × 1600 pixel, file size: 1,006 KB, MIME type: image/png)By Richard Wheeler (Zephyris) 2007. ... Structure of hemoglobin. ... A representation of the 3D structure of myoglobin showing coloured alpha helices. ... For other uses, see Sphere (disambiguation). ... The first solvation shell of a sodium ion dissolved in water An aqueous solution is a solution in which the solvent is water. ... A colloid or colloidal dispersion, is a form of matter intermediate between a true solution and a mixture (suspension). ... Fibrous proteins, also called scleroproteins, are long filamentous protein molecules that form one of the two main classes of tertiary structure protein (the other being globular proteins). ...

Globular structure and solubility

The term globular protein is quite old (dating probably from the 19th century) and is now somewhat archaic given the hundreds of thousands of proteins and more elegant and descriptive structural motif vocabulary. The globular nature of these proteins can be determined without the means of modern techniques, but only by using ultracentrifuges or dynamic light scattering techniques. In an unbranched, chain-like biological molecule, such as a protein or a strand of RNA, a structural motif is a three-dimensional structural element or fold within the chain, which appears also in a variety of other molecules. ... The ultracentrifuge is a centrifuge optimized for spinning a rotor at very high speeds, capable of generating acceleration as high as 1,000,000 G (9,800 km/s²) There are two kinds of ultracentrifuges, the preparative and the analytical ultracentrifuge. ... Scattering is a general physical process whereby some forms of radiation, such as light, sound or moving particles, for example, are forced to deviate from a straight trajectory by one or more localized non-uniformities in the medium through which it passes. ...

The spherical structure is induced by the protein's tertiary structure. The molecule's apolar (hydrophobic tails) groups are bounded towards the molecule's interior whereas polar (hydrophilic heads) ones are bound outwards, allowing dipole-dipole interactions with the solvent, which explains the molecule's solubility. In biochemistry and chemistry, the tertiary structure of a protein or any other macromolecule is its three-dimensional structure, as defined by the atomic coordinates. ... Hydrophobe (from the Greek (hydros) water and (phobos) fear) in chemistry refers to the physical property of a molecule that is repelled by water. ... Polar may refer to: Polsk Ost med KATING WAPOOOOW CHING CHING WOWOWOWOW/Gling, Oink oink. ... Intermolecular forces are electromagnetic forces which act between molecules or between widely separated regions of a macromolecule. ... For other uses, see Solvent (disambiguation). ...

A wide range of roles in the organism

Unlike fibrous proteins which only play a structural function, globular proteins can act as:

• Enzymes, by catalyzing organic reactions taking place in the organism in mild conditions and with a great specificity. Different esterases fulfill this role.
• Messengers, by transmitting messages to regulate biological processes. This function is done by hormones, i.e. insulin etc.
• Transporters of other molecules through membranes
• Stocks of amino acids.
• Regulatory roles are also performed by globular proteins rather than fibrous proteins.

Ribbon diagram of the enzyme TIM, surrounded by the space-filling model of the protein. ... Catalyst redirects here. ... Domains and Kingdoms Nanobes Acytota Cytota Bacteria Neomura Archaea Eukaryota Bikonta Apusozoa Rhizaria Excavata Archaeplastida Rhodophyta Glaucophyta Plantae Heterokontophyta Haptophyta Cryptophyta Alveolata Unikonta Amoebozoa Opisthokonta Choanozoa Fungi Animalia An ericoid mycorrhizal fungus Life on Earth redirects here. ... An esterase is an hydrolase enzyme that splits esters into a acid and an alcohol in a chemical reaction with water called hydrolysis. ... This article is about the NASA space mission. ... For other uses, see Hormone (disambiguation). ... Not to be confused with inulin. ... Look up cell membrane in Wiktionary, the free dictionary. ... This article is about the class of chemicals. ... In the context of government and public services regulation (as a process) is the control of something by rules, as opposed to its prohibition. ...

Members

Among the most known globular proteins is hemoglobin, a member of the globin protein family. Other globular proteins are the immunoglobulins (IgA, IgD, IgE, IgG and IgM), and alpha, beta and gamma globulins. See protein electrophoresis for more information on the different globulins. Nearly all enzymes with major metabolic functions are globular in shape, as well as many signal transduction proteins. Structure of hemoglobin. ... the definition of a globin protein family is shittypoo ... Schematic of antibody binding to an antigen An antibody is a protein complex used by the immune system to identify and neutralize foreign objects like bacteria and viruses. ... Alpha Globulins are a group of globular proteins in plasma, which are highly mobile in alkaline or electricaly charged solutions. ... Beta globulins are a group of globular proteins in plasma that are more mobile in alkaline or electricaly charged solutions than gamma globulins, but less mobile than alpha globulins. ... Schematic representation of a protein electrophoresis gel Gamma globulins, or Igs, are a class of proteins in the blood, identified by their position after serum protein electrophoresis. ... Schematic representation of a protein electrophoresis gel In chemistry and medicine, protein electrophoresis is a method of analysing a mixture of proteins by means of gel electrophoresis, mainly in blood serum (blood plasma is not suitable). ... Structure of the coenzyme adenosine triphosphate, a central intermediate in energy metabolism. ... In biology, signal transduction refers to any process by which a cell converts one kind of signal or stimulus into another, most often involving ordered sequences of biochemical reactions inside the cell, that are carried out by enzymes and linked through second messengers resulting in what is thought of as...