Enzymes systematic names

Common name of enzyme Systematic name of enzyme Enzyme Commission number... 

The formation of the a-(l—f6) glucosyl branches of amylopectin and glycogen is synthesized by branching enzymes (systematic name (1—>)-a-D-glucan (l— 4)-a-D-glucan 6-oc-d-[(1—>4)-oc-D-glucano]-transferase EC 2.4.1.18). 

C/2 Enzyme Systematic name EC number Mode of action... 

Enzymes are classified in terms of the reactions which they catalyse and were formerly named by adding the suffix ase to the substrate or to the process of the reaction. In order to clarify the confusing nomenclature a system has been developed by the International Union of Biochemistry and the International Union of Pure and Applied Chemistry (see Enzyme Nomenclature , Elsevier, 1973). The enzymes are classified into divisions based on the type of reaction catalysed and the particular substrate. The suffix ase is retained and recommended trivial names and systematic names for classification are usually given when quoting a particular enzyme. Any one particular enzyme has a specific code number based upon the new classification. 

Hydrolases. Enzymes catalysing the hydrolytic cleavage ofC —O, C —N and C —C bonds. The systematic name always includes hydrolase but the recommended name is often formed by the addition of ase to the substrate. Examples are esterases, glucosidases, peptidases, proteinases, phospholipases. Other bonds may be cleaved besides those cited, e.g. during the action of sulphatases and phosphatases. 

Sucrose is dextro-rotatory. Fructose shows a laevo-rotation greater in magnitude than the dextro-rotation shown by glucose. Hence as the hydrolysis of sucrose proceeds, the dextro-rotation gradually falls to zero and the solution finally shows a laevo-rotation. This hydrolysis is therefore sometimes called inversion and so the enzyme which catalyses the reaction is known as " invertase. Its more systematic name is, however, sucrase. 

Trehalose (Problem 25.58) is cleaved by enzymes that hydrolyze a-glycosides but not by enzymes that hydrolyze /3-glycosides. What is the structure and systematic name of trehalose ... 

For instance, for the enzyme alcohol dehydrogenase the formal systematic name would be ... 

Enzymes are named by a systematic set of rules that nobody follows. The only given is that enzyme names end in -ase and may have something in them that may say something about the type of reaction they catalyze—such as chymotrypsin, pepsin, and enterokinase (all proteases). 

According to the IUPAC-IUB Enzyme Nomenclature,11 pectinesterase belongs to the carboxyl ester hydrolases (EC 3.1.1.11) and has the systematic name pectin pectyl-hydrolase. The literature also contains the expressions pectin methylesterase, pectin demethoxylase, and pectin methoxylase for the same enzyme. The old name pectase,... 

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. 

First, the true physiological substrates of most esterases are unknown. It is, therefore, hardly practicable to systematically name esterases according to the recommendations of the Enzyme Nomenclature Committee [1], i.e., based on the definite (physiological) role of the enzyme. The difficulty is that the use of nonphysiological substrates during purification and in characterization assays does not contribute to discovering the physiological role of an enzyme. 

In the field of polymer science, the most extensively used transferase is phosphorylase (systematic name (1 4)-a-D-glucan phosphate a-D-glucosyltransferase EC 2.4.1.1). Although this enzyme is responsible for the depolymerization of linear a-( 1 4) glycosidic chains in vivo it can also be used to synthesize linear a-( 1 4) glycosidic chains (amylose) in vitro. 

Rubber is synthesized by plants via a side branch of the isoprenoid pathway by the enzyme rubber transferase (dy-prenyl transferase systematic name poly-dy-polyprenyl-diphosphate isopentenyl-diphosphate polyprenylcistransferase EC 2.5.1.20). Surprisingly, although this process has been studied for decades, due to the labile nature of the rubber transferase and the fact that it is a membrane-associated enzyme present in relatively low abundance, the identification of its protein subunits remain elusive. For some recent reviews on rubber biosynthesis, please refer to [248-251]. 

The systematic name for these enzymes is nucleoside triphosphate a-D-glycosyl phosphate-nucleotidyl transferases (E.C. 2.7.7 group). 

These enzymes are systematically named nucleoside 5 -(o -D-glycopyranosyl pyrophosphate) NAD oxidoreductases (E.C. 1.1.1 group). It should be noted that only a few enzymes are known, except for the ones just mentioned, that catalyze oxidation of a primary carbon atom to a carboxylic acid group. 

This is a systematic name for the enzyme (E.C. 5.1.3.2.). Other enzymes discussed in this subsection belong to the same group. 

For listing organisms their systematic name is preferred. If these are not mentioned in the literature, the names from the respective literature are used. For example if an enzyme from yeast is described without being specified further, yeast will be the entry. This field defines the code numbers for the organisms in which the enzyme with the respective EC number is found. These code numbers (form < >) are displayed together with each entry in all fields of BRENDA where organism-specific information is given. 

Each enzyme is assigned two names. The first is its short, recommended name, convenient for everyday use. The second is the more complete systematic name, which is used when an enzyme must be identified without ambiguity. 

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... 

Individual enzymes are assigned a four-digit number, a systematic name, and a trivial name more commonly used by biochemists. For example, EC (Enzyme Commission) 2.7.1.2 denotes a transferase (major class 2) and indicates that a phosphate group is transferred (subclass 7) and that an alcohol group accepts the phosphate (sub-subclass 1). The final digit denotes that the enzyme is ATP D-glucose-6-phosphotransferase (glucokinase). For the most part, we will use the trivial names accepted by the IUB in our subsequent discussion of enzymes that participate in metabolic pathways. 

An unknown reducing disaccharide is found to be unaffected by invertase enzymes. Treatment with an a-galactosidase cleaves the disaccharide to give one molecule of D-fructose and one molecule of D-galactose. When the disaccharide is treated with excess iodomethane and silver oxide and then hydrolyzed in dilute acid, the products are 2,3,4,6-tetra-(9-methyl-galactose and 1,3,4-tri-O-methylfructose. Propose a structure for this disaccharide, and give its complete systematic name. 

All enzymes are named according to a classification system designed by the Enzyme Commission (EC) of the International Union of Pure and Applied Chemistry (IUPAC) and based on the type of reaction they catalyze. Each enzyme type has a specific, four-integer EC number and a complex, but unambiguous, name that obviates confusion about enzymes catalyzing similar but not identical reactions. In practice, many enzymes are known by a common name, which is usually derived from the name of its principal, specific reactant, with the suffix -ase added. Some common names do not even have -ase appended, but these tend to be enzymes studied and named before systematic classification of enzymes was undertaken. 

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