Enzyme Committee number

During natural evolution, a broad variety of enzymes has been developed, which are classified according to the Nomenclature Committee of the International Union of Biochemistry and Molecular Biology (IUBMB). Thus, for each type of characterized enzyme an EC (Enzyme Commission) number has been provided (see http // www.expasy.ch/enzyme/). For instance, all hydrolases have EC number 3 and further subdivisions are provided by three additional digits, e.g. all lipases (official name triacylglycerol lipases) have the EC number 3.1.1.3 and are thus distinguished from esterases (official name carboxyl esterases) having the EC number 3.1.1.1. This classification is based on the substrate (and cofactor) specificity of an enzyme only, however often very similar amino acid sequences and also related three-dimensional structures can be observed. 

The widely accepted basis of all enzyme classifications are the recommendations of the Enzyme Committee (E.C.) of the International Union of Biochemistry and Molecular Biology (IUBMB)1491. Within this system, enzymatic activities are classified by a four-level hierarchy and each entry is described by a set of four numbers. The first number describes the top level and can be either 1 for oxidoreductases, 2 for transferases, 3 for hydrolases, 4 for lyases, 5 for isomerases or 6 for ligases. The meaning of the three lower hierarchy levels depends on the top level group. As an example, glycogen synthase is classified as 2.4.1.11 here, the 2 stands for transferases, the 4 for glycosyl-transferases, the 1 for hexosyl-transferases and the 11 for the particular subfamily. 

Enzyme classification is primarily based on the recommendations of the Nomenclature Committee of the International Union of Biochemistry and Molecular Biology (lUBMB)", and it describes each type of characterized enzyme for which an EC (Enzyme Commission) number has been provided. EC classes define enzyme function based on the reaction, which is catalyzed by the enzyme. The classification scheme is hierarchical, with four levels. There are six broad categories of function at the top of this hierarchy and about 3500 specific reaction types at the bottom. EC classes are expressed... 

We have departed from the style of the German edition by quoting a few literature references. These have been included with some of the new material, and we hope they will be useful to readers who want more information that can be fitted into a work of this sort. Where possible, we have also given each enzyme its EC (Enzyme Commission) Number, according to the Recommendations (1978) of the Nomenclature Committee of the International Union of Biochemistry (published in Enzyme Nomenclature Academic Press, 1979). 

Since its foundation in 1956 the Nomenclature Committee of the International Union of Biochemistry and Molecular Biology (NC-IUBMB) has continually revised and updated the list of enzymes. Entries for new enzymes have been added, others have been deleted completely, or transferred to another EC number in the original class or to different EC classes, catalyzing other types of chemical reactions. The old numbers have not been allotted to new enzymes instead the place has been left vacant or cross-references given to the changes in nomenclature. 

For non-SI traceable quantities the strategy for introducing traceability has to be different. This concerns a large number of analytes for which no defined molecular structure can be assigned, such as for many enzymes, proteo-homones, tumor markers and cardiac markers. The first and most important step must be the definition of the quantity before it is possible to establish reference systems (reference procedures, materials and reference network laboratories). Whenever possible, a global consensus on the definition of the measurand should be achieved. Consequently, definition of the measurand and establishment of reference systems is the objective of several working groups and committees of the Scientific Division of IFCC. 

This URL is an update of the IUBMB recommendations of names for enzymes. This site is the responsibility of the Nomenclature Committee of NC-IUBMB. This section gives balanced equations for enzyme-catalyzed reactions and certain references and information, arranged by EC number. Links are provided to BRENDA, EXPASY, GDT, KEGG, UM-BBD, ERGO, and PDP. 

Databases such as Enzyme [12], Brenda [5], Ligand [28] and EMP [6] contain enzymes which are involved in a large number of reactions. Each enzyme with known enzyme function are catalogued and named by a nomenclature committee. Also included in the databases is information on the reaction and specificity of the enzyme and the various conditions the enzyme will be active under. Information about the structure and stability of the enzyme and the preparation of the reaction may also be included. 

In the past, 25 ° C was the commonly used temperature for enzyme assays this temperature has the disadvantage of requiring cooling of the reaction chamber or cuvets and of course slower enzyme reaction rates as compared to 30° C or 3 7 ° C. A number of professional societies (e.g., International Federation of Clinical Chemistry (IFCC), National Committee for Clinical Laboratory Standards... 

Immunological methods for enzymes, more specifically isoenzymes, such as lactate dehydrogenase-1 (167, 168), mitochondrial aspartate aminotransferase (169), prostatic acid phosphatase (170, 171,172), and creatine kinase-MB (173, 174, 175), have been in use in the clinical laboratory for 10 years. However, the use of the immunological rather than catalytic properties of enzymes has not provided the opportunities for standardization that was anticipated a number of years ago (176, 177, 178). It is only within the last year that a working group on CK-MB mass assay was formed under the auspices of the Standards Committee of the American Association for Clinical Chemistry (AACC). The objective of this working group is to prepare a reference material to calibrate methods that are based on the principle of CK-MB mass measurement. 

The ENZYME database (http //www.expasy.ch/enzyme/) provides basic information about specific enzymes. It is based on the recommendations of the Nomenclature Committee of the International Union of Biochemistry and Molecular Biology. In this database, you can obtain the EC number of any enzyme, its recommended name, alternative names, cofactors, and human diseases associated with the enzyme. You can trace the enzyme from its name to the reaction it catalyses—to the metabolic pathway(s) in which it participates—to the large and intricate Boehringer Mannheim Biochemical Pathways Wallchart. You also can search the database by metabolites or pathways. 

Protein enzymes have been classified into six major classes according to the nature of the reaction they catalyze. Enzyme Commission (EC) numbers have been assigned to all enzymes by the Nomenclature Committee of the International Union of Biochemistry and Molecular Biology. Generally, each enzyme has a unique number, but there are exceptions—the restriction enzymes which cut nucleic acids are one such exceptional group. The official name and munber for this group of enzymes (and there are thousands of them) is Type II site-specific deoxyribonuclease, EC 3.1.21.4. Many other details of enzymes and their kinetics are given in Chap. 5. 

There does not seem to be any information regarding the other rifamy-cins, rifabutin (a weak enzyme inducer) and rifapentine (a moderate enzyme inducer). However, the manufacturers and the UK Committee on Safety of Medicines warn that rifabutin may possibly reduce the effects of a number of drugs, including oral antidiabetics. ... 

NOTE 1 Enzyme names and enzyme numbers are taken from Enzyme Nomenclature, Recommendations (1978) of the Nomenclature Committee of the International Union of Biochemistry Academic Press, New York. With few exceptions, the recommended names are listed first in Section 34, followed by Other Names or synonyms in a set of brackets, and/or finally followed by the official enzyme numbers in a set of parentheses.]... 

The EC numbers of enzymes are from the Recommendations (1992) of the Nomenclature Committee of the International Union of Biochemistry and Molecular Biology ( Enzyme Nomenclature , Academic Press, 1992). 

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