Enzyme Commission code

The title retains the trivial name for enzymes with the systematic name of urea amidohydrolase and the Enzyme Commission code number of EC 3.5.1.5. Ureases are hydrolases acting on C-N bonds (nonpeptide) in linear amides and thus belong to a group that includes glutaminase, form-amidase, and formyltetrahydrofolate deformylase. The title is plural to emphasize that urease activity may be exhibited by several protein species. Urease, singular, has come to mean by common usage, that particular enzymic protein first crystallized by Sumner from jack bean... 

The International Union of Biochemistry has recommended that enzymes have three names, namely a systematic name, which shows the reaction being catalysed and the type of reaction based on the classification in Table A7.1, a recommended trivial name and a four figure Enzyme Commission code (EC code). Nearly all systematic and trivial enzyme names have the suffix -ase. Systematic names show, often in semi-chemical equation form, the conversion the enzyme promotes and the class of the enzyme. Trivial names are usually based on the function of the enzyme but may also include or be based on the name of the substrate. However, some trivial names in current use are historical and bear no relationship to the action of the enzyme or its substrate, for example, pepsin and trypsin are the names commonly used for two enzymes that catalyse the breakdown of proteins during digestion. The Enzyme Commission s code is unique for each enzyme. It is based on the classification in Table A7.1 but further subdivides each class of enzyme according to how it functions. The full code is... 

The first Enzyme Commission, in its 1961 report, devised a system for classification of enzymes that also serves as a basis for assigning code numbers to them. Every enzyme has got a 4-digit number EC A.B.C.D. where EC stands for Enzyme Commission with the following properties encoded ... 

All enzymes already mentioned, except oligo-D-galactosiduronate hydrolase, are included in the Enzyme Nomenclature of the IUPAC-IUB Enzyme Commission,11 and their code numbers and suitably modified, systematic names are used herein. 

A-17 According to lUB system enz)mies are grouped in six major classes. Each with sub classes based on the t) e of reaction catalyzed. Systemic classification of enzymes based on numbering system is used. Each enzyme is assigned a code number or EC (enzyme commission number) four-digit classification number and a systematic name, which identifies the reaction catalyzed. 

When searching for a drug the U.S. Adopted Name is the first choice, but since 1998 it is also possible to search using CAS registry numbers. Note that it is only possible to search on the fields of brand names. Enzyme Commission Numbers and lab codes if they are given in the original literature source. The indexers at BioSciences Information Service will not add them to the database. 

According to the Enzyme Commission (EC) system, enzymes are classified according to their function and substrates. The code numbers contain four elements, with the first number indicating one of six main divisions (classes) and the following numbers indicating subclasses. The six main divisions are ... 

Table 4.1 The Enzyme Commission s system of classification of enzymes and assigning code numbers (Palmer, 2001)...

There are basically two strategies for carrying out biotransformations (I) to use pure or partially purified enzymes isolated by the investigator or purchased from a commercial supplier, or (2) to use whole cells. Enzymes are categorized by the Enzyme Commission (EC) according to their functions (Table 2.1), and each individual enzyme is given a unique code made up of four numbers, such as 2.1.2.4. These reference numbers are derived as follows ... 

Tissue was homogenised with an equal volume of buffer (2 ml Tris-HCl (pH 8.0), 0.1 ml mercaptoethanol, 10 g sucrose, and 25 mg NADP per 100 ml H2O - adjusted to pH 7.2 with HCl). Electrophoresis was performed on cellulose acetate plates (Titan III Helena Laboratories). A preliminary survey of 42 enzymes detected four enzyme loci, coding for four different enzyme systems that were polymorphic and consistently resolvable. These enzymes were used for the analysis and were as follows (abbreviation and enzyme commission number in parentheses) hexokinase (HK, E.C. 2.7.1.1), mannose-6-phosphate isomerase (MPI, E.C. 5.3.1.8), 6-phosphogluconate dehydrogenase (6PGD, E.C. 1.1.1.44), and phosphoglucose isomerase (PGI, E.C. 5.3.1.9). 

Code number assigned by the Enzyme Commission (EC) of the International Union of Biochemistry. 

By the late 1950s, enzyme nomenclature was in confusion. Without any guiding authority, the increase in known enzymes had led to the assignment of misleading or inappropriate names, and in many cases the same enzyme became known by several names while some catalytically different enzymes were identically named. In 1961, the first Enzyme Commission reported a system for enzyme classification and the assignment of code numbers. 

TABLE 5.3 Some examples of enzyme commission classification and coding... 

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