Prosthetic group

	Email		Print
	Bookmark		Link

Prosthetic group

A prosthetic group is a non-protein (non-amino acid

Amino acid

In chemistry, an amino acid is a molecule containing both amine and carboxyl functional groups. These molecules are particularly important in biochemistry, where this term refers to alpha-amino acids with the general formula H2NCHRCOOH, where R is an organic substituent....
) component of a conjugated protein

Conjugated protein

A conjugated protein is a protein that functions in interaction with other chemical groups attached by covalent bonds or by weak interactions....
that is required for the protein's biological activity. The prosthetic group may be organic

Organic compound

An organic compound is any member of a large class of chemical compounds whose molecules contain carbon. For historical reasons discussed below, a few types of compounds such as carbonates, simple oxides of carbon and cyanides, as well as the allotropes of carbon, are considered Inorganic compound....
(such as a vitamin

Vitamin

A vitamin is an organic compound required as a nutrient in tiny amounts by an organism. A compound is called a vitamin when it cannot be biosynthesis in sufficient quantities by an organism, and must be obtained from the diet....
, sugar

Sugar

Sugar is a class of edible crystalline substances, mainly sucrose, lactose, and fructose. Human taste buds interpret its flavor as sweet. Sugar as a basic food carbohydrate primarily comes from sugar cane and from sugar beet, but also appears in fruit, honey, sorghum, sugar maple , and in many other sources....
, RNA

RNA

Ribonucleic acid is a type of molecule that consists of a long chain of nucleotide units. Each nucleotide consists of a nucleobase, a ribose sugar, and a phosphate....
, phosphate

Phosphate

A phosphate, an inorganic chemical, is a Salt of phosphoric acid. Inorganic phosphates are mining to obtain phosphorus for use in agriculture and industry....
or lipid

Lipid

Lipids are broadly defined as any fat-soluble , naturally-occurring molecule, such as fats, oils, waxes, cholesterol, sterols, fat-soluble vitamins , monoglycerides, diglycerides, phospholipids, and others....
) or inorganic (such as a metal

Metal

In chemistry, a metal is a chemical element whose atoms readily lose electrons to form positive ions , and form metallic bonds between other metal atoms and ionic bonds between nonmetal atoms....
ion). Prosthetic groups are bound tightly to proteins and may even be attached through a covalent bond

Covalent bond

A covalent bond is a form of chemical bonding that is characterized by the sharing of pairs of electrons between atoms, or between atoms and other covalent bonds....
. They often play an important role in enzyme catalysis

Enzyme catalysis

Enzyme catalysis is the catalysis of chemical reactions by specialized proteins known as enzymes. Catalysis of biochemical reactions in the cell is vital due to the very low reaction rates of the uncatalysed reactions....
. A protein without its prosthetic group is called an apoprotein

Apoprotein

Apoprotein can refer to:*Apoenzyme, the protein part of an enzyme without its characteristic prosthetic group.*Apolipoprotein, a lipid-binding protein that is a constituent of the plasma lipoprotein....
, while a protein combined with its prosthetic group is called a holoprotein

Holoprotein

Holoprotein is an apoprotein combined with its prosthetic group....
.

Discussion

Ask a question about 'Prosthetic group'

Start a new discussion about 'Prosthetic group'

Answer questions from other users

Full Discussion Forum

Encyclopedia

A prosthetic group is a non-protein (non-amino acid

Amino acid

Conjugated protein

Organic compound

Vitamin

Sugar

RNA

Ribonucleic acid is a type of molecule that consists of a long chain of nucleotide units. Each nucleotide consists of a nucleobase, a ribose sugar, and a phosphate....
, phosphate

Phosphate

A phosphate, an inorganic chemical, is a Salt of phosphoric acid. Inorganic phosphates are mining to obtain phosphorus for use in agriculture and industry....
or lipid

Lipid

Metal

Covalent bond

Enzyme catalysis

Apoprotein

Holoprotein

Holoprotein is an apoprotein combined with its prosthetic group....
. A non-covalently bound prosthetic group cannot generally be removed from the holoprotein without denaturating the protein. Thus, the term "prosthetic group" is a very general one and its main emphasis is on the tight character of its binding to the apoprotein. It defines a structural property, with oppostion of the term "coenzyme" that defines a functional property.

Prosthetic groups are a subset of cofactors

Cofactor (biochemistry)

A cofactor is a non-protein chemical compound that is bound to an enzyme and is required for catalysis. They can be considered "helper molecules/ions" that assist in biochemical transformations....
. Loosely bound metal ions and coenzymes are still cofactors, but are generally not called prosthetic groups. In enzymes, prosthetic groups are involved in the catalytic mechanism and required for activity. Other prosthetic groups have structural properties. This is the case for the sugar and lipid moieties in glycoproteins and lipoproteins or RNA

RNA

Ribonucleic acid is a type of molecule that consists of a long chain of nucleotide units. Each nucleotide consists of a nucleobase, a ribose sugar, and a phosphate....
in ribosomes. They can be very large, representing the major part of the protein in proteoglycans for instance.

The heme

Heme

A heme or haem is a prosthetic group that consists of an iron atom contained in the center of a large heterocyclic organic ring called a porphyrin....
group in hemoglobin

Hemoglobin

Hemoglobin is the iron-containing oxygen-transport metalloprotein in the red blood cells of vertebrates, and the tissues of some invertebrates....
is a prosthetic group. Further examples of organic prosthetic groups are vitamin derivatives: thiamine pyrophosphate

Thiamine pyrophosphate

Thiamine pyrophosphate , or thiamine diphosphate , is a thiamine Derivative which is produced by the enzyme thiamine pyrophosphatase. Thiamine pyrophosphate is a coenzyme that is present in all living systems, in which it catalyzes several Biochemistry reactions....
, pyridoxal-phosphate

Pyridoxal-phosphate

Pyridoxal-phosphate is a prosthetic group of some enzymes. It is the active form of vitamin B6 which comprises three natural organic compounds, pyridoxal, pyridoxamine and pyridoxine....
and biotin

Biotin

Biotin, also known as vitamin H or B7, has the chemical formula C10H16N2O3S , is a water-soluble B-complex vitamin which is composed of an ureido ring fused with a tetrahydrothiophene ring....
. Since prosthetic groups are often vitamins or made from vitamins, this is one of the reasons why vitamins are required in the human diet. Inorganic prosthetic groups are usually transition metal

Transition metal

In chemistry, the term transition metal has two possible meanings:*It commonly refers to any element in the d-block of the periodic table, including the group 12 element elements zinc, cadmium and Mercury ....
ions such as iron

Iron

Iron is a chemical element with the symbol Fe and atomic number 26. Iron is a Group 8 element and period 4 element. Iron is lustrous and silvery in color....
(in heme

Heme

A heme or haem is a prosthetic group that consists of an iron atom contained in the center of a large heterocyclic organic ring called a porphyrin....
groups, for example in cytochrome c oxidase

Cytochrome c oxidase

The enzyme cytochrome c oxidase or Complex IV is a large transmembrane protein complex found in bacteria and the mitochondrion.It is the last enzyme in the respiratory electron transport chain of mitochondria located in the mitochondrial membrane....
and hemoglobin

Hemoglobin

Hemoglobin is the iron-containing oxygen-transport metalloprotein in the red blood cells of vertebrates, and the tissues of some invertebrates....
), zinc

Zinc

Zinc is a metallic chemical element with the symbol Zn and atomic number 30. It is a first-row transition metal of the group 12 element of the periodic table....
(for example in carbonic anhydrase

Carbonic anhydrase

The carbonic anhydrases form a family of enzymes that catalyst the rapid conversion of carbon dioxide to bicarbonate and Hydronium ions, a reaction that occurs rather slowly in the absence of a catalyst....
), copper

Copper

Copper is a chemical element with the symbol Cu and atomic number 29.It is a ductile metal with very high thermal and electrical conductivity....
(for example in complex IV of the respiratory chain) and molybdenum

Molybdenum

Molybdenum , is a Group 6 element chemical element with the symbol Mo and atomic number 42. It has the List of elements by melting point melting point of any element....
(for example in nitrate reductase

Nitrate reductase

Nitrate reductase enzymes are a group of enzymes that reduce nitrate to nitrite.* Nitrate reductase - is a large and complex enzyme with multiple subunits and a mass of ~800 kDa....
).

List of prosthetic groups

Prosthetic group	Function	Distribution >- \| Flavin mononucleotide Flavin mononucleotide Flavin mononucleotide , or riboflavin-5'-phosphate, is a biomolecule produced from riboflavin by the enzyme riboflavin kinase and functions as prosthetic group of various oxidoreductases including NADH dehydrogenase....	Redox Redox Redox describes all chemical reactions in which atoms have their oxidation number changed.This can be either a simple redox process such as the oxidation of carbon to yield carbon dioxide or the reduction of carbon by hydrogen to yield methane , or it can be a complex process such as the oxidation of sugar in the human body through a ser... reactions	Bacteria Bacteria The Bacteria are a large group of unicellular microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals.... , archaea Archaea The Archaea are a group of single-celled microorganisms. A single individual or species from this domain is called an archaeon . Archaea, like bacteria, are prokaryotic.... and eukaryote Eukaryote Animals, plants, fungus, and protists are eukaryotes , organisms whose Cell are organized into complex structures enclosed within Cell membrane.... s \|- \| Flavin adenine dinucleotide FAD In biochemistry, flavin adenine dinucleotide is a redox Cofactor involved in several important reactions in metabolism. FAD can exist in two different redox states and its biochemical role usually involves changing between these two states....	Redox Redox Redox describes all chemical reactions in which atoms have their oxidation number changed.This can be either a simple redox process such as the oxidation of carbon to yield carbon dioxide or the reduction of carbon by hydrogen to yield methane , or it can be a complex process such as the oxidation of sugar in the human body through a ser... reactions	Bacteria Bacteria The Bacteria are a large group of unicellular microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals.... , archaea Archaea The Archaea are a group of single-celled microorganisms. A single individual or species from this domain is called an archaeon . Archaea, like bacteria, are prokaryotic.... and eukaryote Eukaryote Animals, plants, fungus, and protists are eukaryotes , organisms whose Cell are organized into complex structures enclosed within Cell membrane.... s \|- \|Pyrroloquinoline quinone Pyrroloquinoline quinone Pyrroloquinoline quinone was discovered by Houge as the third redox cofactor after nicotinamide and flavin in bacteria. Anthony and Zatman also found the unknown redox cofactor in alcohol dehydrogenase and named Metoxatin....	Redox Redox Redox describes all chemical reactions in which atoms have their oxidation number changed.This can be either a simple redox process such as the oxidation of carbon to yield carbon dioxide or the reduction of carbon by hydrogen to yield methane , or it can be a complex process such as the oxidation of sugar in the human body through a ser... reactions	Bacteria Bacteria The Bacteria are a large group of unicellular microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals.... \|- \|Pyridoxal phosphate	Transamination Transamination There are two chemical reactions known as transamination . The first is the reaction between an amino acid and an alpha-keto acid. The amino group is transferred from the former to the latter; this results in the amino acid being converted to the corresponding a-keto acid, while the reactant a-keto acid is converted to the corresponding amin... , decarboxylation Decarboxylation Decarboxylation is any chemical reaction in which a carboxyl group is split off from a compound as carbon dioxide .... and deamination Deamination Deamination is the removal of an amine group from a molecule.In the human body, deamination takes place in the liver. Deamination is the process by which amino acids are broken down when too much protein has been taken in....	Bacteria Bacteria The Bacteria are a large group of unicellular microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals.... , archaea Archaea The Archaea are a group of single-celled microorganisms. A single individual or species from this domain is called an archaeon . Archaea, like bacteria, are prokaryotic.... and eukaryote Eukaryote Animals, plants, fungus, and protists are eukaryotes , organisms whose Cell are organized into complex structures enclosed within Cell membrane.... s \|- \|Biotin Biotin Biotin, also known as vitamin H or B7, has the chemical formula C10H16N2O3S , is a water-soluble B-complex vitamin which is composed of an ureido ring fused with a tetrahydrothiophene ring....	Carboxylation Carboxylation Carboxylation in chemistry is a chemical reaction in which a carboxylic acid group is introduced in a Substrate . The opposite reaction is decarboxylation....	Bacteria Bacteria The Bacteria are a large group of unicellular microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals.... , archaea Archaea The Archaea are a group of single-celled microorganisms. A single individual or species from this domain is called an archaeon . Archaea, like bacteria, are prokaryotic.... and eukaryote Eukaryote Animals, plants, fungus, and protists are eukaryotes , organisms whose Cell are organized into complex structures enclosed within Cell membrane.... s \|- \| Methylcobalamin	Methylation Methylation Methylation in the chemical sciences denotes the attachment or substitution of a methyl on various Substrate . This term is commonly used in chemistry, biochemistry, soil science and the biological sciences.... and isomerisation Isomerisation In chemistry isomerisation is the process by which one molecule is transformed into another molecule which has exactly the same atoms, but the atoms are rearranged e.g....	Bacteria Bacteria The Bacteria are a large group of unicellular microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals.... , archaea Archaea The Archaea are a group of single-celled microorganisms. A single individual or species from this domain is called an archaeon . Archaea, like bacteria, are prokaryotic.... and eukaryote Eukaryote Animals, plants, fungus, and protists are eukaryotes , organisms whose Cell are organized into complex structures enclosed within Cell membrane.... s \|- \|Thiamine pyrophosphate Thiamine pyrophosphate Thiamine pyrophosphate , or thiamine diphosphate , is a thiamine Derivative which is produced by the enzyme thiamine pyrophosphatase. Thiamine pyrophosphate is a coenzyme that is present in all living systems, in which it catalyzes several Biochemistry reactions....	Decarboxylation Decarboxylation Decarboxylation is any chemical reaction in which a carboxyl group is split off from a compound as carbon dioxide ....	Bacteria Bacteria The Bacteria are a large group of unicellular microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals.... , archaea Archaea The Archaea are a group of single-celled microorganisms. A single individual or species from this domain is called an archaeon . Archaea, like bacteria, are prokaryotic.... and eukaryote Eukaryote Animals, plants, fungus, and protists are eukaryotes , organisms whose Cell are organized into complex structures enclosed within Cell membrane.... s \|- \|Heme Heme A heme or haem is a prosthetic group that consists of an iron atom contained in the center of a large heterocyclic organic ring called a porphyrin....	Oxygen Oxygen Oxygen no O2 produced; 2) O2 produced, but absorbed in oceans & seabed rock; 3) O2 starts to gas out of the oceans, but is absorbed by land surfaces and formation of ozone layer; 4-5) O2 sinks filled and the gas accumulates]]... binding and redox Redox Redox describes all chemical reactions in which atoms have their oxidation number changed.This can be either a simple redox process such as the oxidation of carbon to yield carbon dioxide or the reduction of carbon by hydrogen to yield methane , or it can be a complex process such as the oxidation of sugar in the human body through a ser... reactions	Bacteria Bacteria The Bacteria are a large group of unicellular microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals.... , archaea Archaea The Archaea are a group of single-celled microorganisms. A single individual or species from this domain is called an archaeon . Archaea, like bacteria, are prokaryotic.... and eukaryote Eukaryote Animals, plants, fungus, and protists are eukaryotes , organisms whose Cell are organized into complex structures enclosed within Cell membrane.... s \|- \|Molybdopterin Molybdopterin Molybdopterins are a class of cofactor found in most molybdenum and all tungsten enzymes. It consists of a pyranopterin, a complex heterocycle featuring a pyran fused to a pterin ring....	Oxygenation Oxygenation Oxygenation refers to either the amount of oxygen in a medium or to the process of adding oxygen to a medium to increase its oxygen content.... reactions	Bacteria Bacteria The Bacteria are a large group of unicellular microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals.... , archaea Archaea The Archaea are a group of single-celled microorganisms. A single individual or species from this domain is called an archaeon . Archaea, like bacteria, are prokaryotic.... and eukaryote Eukaryote Animals, plants, fungus, and protists are eukaryotes , organisms whose Cell are organized into complex structures enclosed within Cell membrane.... s \|- \|Lipoic acid Lipoic acid Lipoic acid is an organic compound, one enantiomer of which is an essential cofactor for many enzyme complexes. The molecule consists of a carboxylic acid and a cyclic Disulfide bond....	Redox Redox Redox describes all chemical reactions in which atoms have their oxidation number changed.This can be either a simple redox process such as the oxidation of carbon to yield carbon dioxide or the reduction of carbon by hydrogen to yield methane , or it can be a complex process such as the oxidation of sugar in the human body through a ser... reactions	Bacteria Bacteria The Bacteria are a large group of unicellular microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals.... , archaea Archaea The Archaea are a group of single-celled microorganisms. A single individual or species from this domain is called an archaeon . Archaea, like bacteria, are prokaryotic.... and eukaryote Eukaryote Animals, plants, fungus, and protists are eukaryotes , organisms whose Cell are organized into complex structures enclosed within Cell membrane.... s

Prosthetic group

List of prosthetic groups

See also

External links