EC number
Encyclopedia
- This article is about the Enzyme Commission codes. For the European Commission system for coding chemicals, see EC-NoEC-NoThe European Commission number, or EC number, also known as EC-No and EC#, is the seven-digit code that is assigned to chemical substances that are commercially available within the European Union...
.
The Enzyme Commission number (EC number) is a numerical classification
Numbering scheme
There are many different numbering schemes for assigning nominal numbers to entities. These generally require an agreed set of rules, or a central coordinator. The schemes can be considered to be examples of a primary key of a database management system table, whose table definitions require a...
scheme for enzyme
Enzyme
Enzymes are proteins that catalyze chemical reactions. In enzymatic reactions, the molecules at the beginning of the process, called substrates, are converted into different molecules, called products. Almost all chemical reactions in a biological cell need enzymes in order to occur at rates...
s, based on the chemical reaction
Chemical reaction
A chemical reaction is a process that leads to the transformation of one set of chemical substances to another. Chemical reactions can be either spontaneous, requiring no input of energy, or non-spontaneous, typically following the input of some type of energy, such as heat, light or electricity...
s they catalyze
Catalysis
Catalysis is the change in rate of a chemical reaction due to the participation of a substance called a catalyst. Unlike other reagents that participate in the chemical reaction, a catalyst is not consumed by the reaction itself. A catalyst may participate in multiple chemical transformations....
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As a system of enzyme nomenclature, every EC number is associated with a recommended name for the respective enzyme.
Strictly speaking, EC numbers do not specify enzymes, but enzyme-catalyzed reactions. If different enzymes (for instance from different organisms) catalyze the same reaction, then they receive the same EC number. By contrast, UniProt
UniProt
UniProt is a comprehensive, high-quality and freely accessible database of protein sequence and functional information, many of which are derived from genome sequencing projects...
identifiers uniquely specify a protein by its amino acid sequence.
Format of number
Every enzyme code consists of the letters "EC" followed by four numbers separated by periods. Those numbers represent a progressively finer classification of the enzyme.For example, the tripeptide aminopeptidases have the code "EC 3.4.11.4", whose components indicate the following groups of enzymes:
- EC 3 enzymes are hydrolaseHydrolaseIn biochemistry, a hydrolase is an enzyme that catalyzes the hydrolysis of a chemical bond. For example, an enzyme that catalyzed the following reaction is a hydrolase:-Nomenclature:...
s (enzymes that use waterWaterWater is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...
to break up some other molecule) - EC 3.4 are hydrolases that act on peptide bondPeptide bondThis article is about the peptide link found within biological molecules, such as proteins. A similar article for synthetic molecules is being created...
s - EC 3.4.11 are those hydrolases that cleave off the amino-terminal amino acidAmino acidAmino acids are molecules containing an amine group, a carboxylic acid group and a side-chain that varies between different amino acids. The key elements of an amino acid are carbon, hydrogen, oxygen, and nitrogen...
from a polypeptide - EC 3.4.11.4 are those that cleave off the amino-terminal end from a tripeptideTripeptideA tripeptide is a peptide consisting of three amino acids joined by peptide bonds.Examples of tripeptides are:*Eisenin is a peptide with immunological activity that is isolated from the Japanese marine alga, Eisenia bicyclis, which more commonly is known as, Arame*GHK-Cu is a human copper binding...
Top level codes
| Group | Reaction catalyzed | Typical reaction | Enzyme example(s) with trivial name |
|---|---|---|---|
| EC 1 Oxidoreductase Oxidoreductase In biochemistry, an oxidoreductase is an enzyme that catalyzes the transfer of electrons from one molecule to another... s |
To catalyze oxidation/reduction reactions; transfer of H and O atoms or electron Electron The electron is a subatomic particle with a negative elementary electric charge. It has no known components or substructure; in other words, it is generally thought to be an elementary particle. An electron has a mass that is approximately 1/1836 that of the proton... s from one substance to another |
AH + B → A + BH (reduced) A + O → AO (oxidized) |
Dehydrogenase Dehydrogenase A dehydrogenase is an enzyme that oxidises a substrate by a reduction reaction that transfers one or more hydrides to an electron acceptor, usually NAD+/NADP+ or a flavin coenzyme such as FAD or FMN.-Examples:... , oxidase Oxidase An oxidase is any enzyme that catalyzes an oxidation-reduction reaction involving molecular oxygen as the electron acceptor. In these reactions, oxygen is reduced to water or hydrogen peroxide .... |
| EC 2 Transferase Transferase In biochemistry, a transferase is an enzyme that catalyzes the transfer of a functional group from one molecule to another . For example, an enzyme that catalyzed this reaction would be a transferase:In this example, A would be the donor, and B would be the acceptor... s |
Transfer of a functional group Functional group In organic chemistry, functional groups are specific groups of atoms within molecules that are responsible for the characteristic chemical reactions of those molecules. The same functional group will undergo the same or similar chemical reaction regardless of the size of the molecule it is a part of... from one substance to another. The group may be methyl-, acyl-, amino- or phosphate group |
AB + C → A + BC | Transaminase Transaminase In biochemistry, a transaminase or an aminotransferase is an enzyme that catalyzes a type of reaction between an amino acid and an α-keto acid. To be specific, this reaction involves removing the amino group from the amino acid, leaving behind an α-keto acid, and transferring it to the... , kinase Kinase In chemistry and biochemistry, a kinase is a type of enzyme that transfers phosphate groups from high-energy donor molecules, such as ATP, to specific substrates, a process referred to as phosphorylation. Kinases are part of the larger family of phosphotransferases... |
| EC 3 Hydrolase Hydrolase In biochemistry, a hydrolase is an enzyme that catalyzes the hydrolysis of a chemical bond. For example, an enzyme that catalyzed the following reaction is a hydrolase:-Nomenclature:... s |
Formation of two products from a substrate by hydrolysis Hydrolysis Hydrolysis is a chemical reaction during which molecules of water are split into hydrogen cations and hydroxide anions in the process of a chemical mechanism. It is the type of reaction that is used to break down certain polymers, especially those made by condensation polymerization... |
AB + H2O → AOH + BH | Lipase Lipase A lipase is an enzyme that catalyzes the formation or cleavage of fats . Lipases are a subclass of the esterases.Lipases perform essential roles in the digestion, transport and processing of dietary lipids in most, if not all, living organisms... , amylase Amylase Amylase is an enzyme that catalyses the breakdown of starch into sugars. Amylase is present in human saliva, where it begins the chemical process of digestion. Food that contains much starch but little sugar, such as rice and potato, taste slightly sweet as they are chewed because amylase turns... , peptidase |
| EC 4 Lyase Lyase In biochemistry, a lyase is an enzyme that catalyzes the breaking of various chemical bonds by means other than hydrolysis and oxidation, often forming a new double bond or a new ring structure... s |
Non-hydrolytic addition or removal of groups from substrates. C-C, C-N, C-O or C-S bonds may be cleaved | RCOCOOH → RCOH + CO2 or [X-A-B-Y] → [A=B + X-Y] |
Decarboxylase |
| EC 5 Isomerase Isomerase In biochemistry, an isomerase is an enzyme that catalyzes the structural rearrangement of isomers. Isomerases thus catalyze reactions of the formwhere B is an isomer of A.-Nomenclature:... s |
Intramolecule rearrangement, i.e. isomer Isomer In chemistry, isomers are compounds with the same molecular formula but different structural formulas. Isomers do not necessarily share similar properties, unless they also have the same functional groups. There are many different classes of isomers, like stereoisomers, enantiomers, geometrical... ization changes within a single molecule |
AB → BA | Isomerase Isomerase In biochemistry, an isomerase is an enzyme that catalyzes the structural rearrangement of isomers. Isomerases thus catalyze reactions of the formwhere B is an isomer of A.-Nomenclature:... , mutase Mutase A mutase is an enzyme that catalyzes the shifting of a functional group from one position to another within the same molecule. Examples of this are bisphosphoglycerate mutase, which appears in red blood cells and phosphoglycerate mutase, which acts in glycolysis. In glycolysis, it changes... |
| EC 6 Ligase Ligase In biochemistry, ligase is an enzyme that can catalyse the joining of two large molecules by forming a new chemical bond, usually with accompanying hydrolysis of a small chemical group dependent to one of the larger molecules... s |
Join together two molecules by synthesis of new C-O, C-S, C-N or C-C bonds Covalent bond A covalent bond is a form of chemical bonding that is characterized by the sharing of pairs of electrons between atoms. The stable balance of attractive and repulsive forces between atoms when they share electrons is known as covalent bonding.... with simultaneous breakdown of ATP Adenosine triphosphate Adenosine-5'-triphosphate is a multifunctional nucleoside triphosphate used in cells as a coenzyme. It is often called the "molecular unit of currency" of intracellular energy transfer. ATP transports chemical energy within cells for metabolism... |
X + Y+ ATP → XY + ADP + Pi | Synthetase |
History
The enzyme nomenclature scheme was developed starting in 1955, when the International Congress of Biochemistry in BrusselsBrussels
Brussels , officially the Brussels Region or Brussels-Capital Region , is the capital of Belgium and the de facto capital of the European Union...
set up an Enzyme Commission.
The first version was published in 1961.
The current sixth edition, published by the International Union of Biochemistry and Molecular Biology
International Union of Biochemistry and Molecular Biology
The International Union of Biochemistry and Molecular Biology is an international non-governmental organisation concerned with biochemistry and molecular biology...
in 1992, contains 3196 different enzymes.
See also
- EC number (chemistry)
- IdentifierIdentifierAn identifier is a name that identifies either a unique object or a unique class of objects, where the "object" or class may be an idea, physical [countable] object , or physical [noncountable] substance...
- International Union of Biochemistry and Molecular BiologyInternational Union of Biochemistry and Molecular BiologyThe International Union of Biochemistry and Molecular Biology is an international non-governmental organisation concerned with biochemistry and molecular biology...
- TC numberTC numberTransporter Classification database is an International Union of Biochemistry and Molecular Biology approved classification system for membrane transport proteins including ion channels...
(classification of membrane transport proteins) - List of enzymes
- List of EC numbers
External links
- Enzyme Nomenclature
- Enzyme nomenclature database — by ExPASyExPASyExPASy is a bioinformatics resource portal operated by the Swiss Institute of Bioinformatics and in particular the SIB Web Team. It is an extensible and integrative portal accessing many scientific resources, databases and software tools in different areas of life sciences...
- List of all EC numbers — by BRENDABRENDABRENDA is an enzyme information system representing one of the most comprehensive enzyme repositories.- Introduction :...
- Browse PDB structures by EC number