Full access CHIR-99021 to relevant data would require the strict compliance with nomenclature standards in the paper; data integration and comparison of data from different labs and methods is only possible if experimental standards are used and experimental meta-data are fully documented in publications. With the

current state of science the task of data integration and systematic experimental documentation can only be accomplished by databases. This article illuminates a number of principles and shortcomings in the current state of standardisation. Since enzymology has a long history many enzyme names are not unique. In many cases the same enzymes became known by several different names, while conversely the same name was sometimes given to different enzymes. Many names conveyed little or no information on the enzymatic function, and similar names were sometimes given to enzymes of quite different types. Recently the unfortunate habit of using gene names for enzymes has become common practice in some areas of molecular biology. In 1956 the International Commission BTK inhibitor purchase on Enzymes was created by the International Union of Biochemistry. Since then an elaborated enzyme classification system providing hierarchical EC numbers as well as systematic names and recommended names has been established (see also Cornish-Bowden on current

IUBMB recommendations, 2014). In the EC number

system an enzyme is not defined by its name but by the reaction it catalyses. In some cases where this is not sufficient, additional criteria are employed such as cofactor specificity or stereospecificity of the reaction. The EC number classifies the enzyme according to the type of reaction it catalyses. Six main classes have been established: (1) oxidoreductases; Unoprostone (2) transferases; (3) hydrolases; (4) lyases; (5) isomerases and (6) ligases. Each main class is attributed with sub- and sub-sub-classes further defining reaction partners, cofactors and type of substrate. Since the start of the project the list of classified enzymes has grown steadily and meanwhile comprises about 5300 (January 2014) valid EC classes plus several hundred deleted and transferred classes (McDonald et al., 2009). Detailed rules for naming an enzyme have been developed and are published on the website of the IUBMB enzyme database. Each classified enzyme receives two names: This name shows the action of the enzymes as clearly as possible. Thus it often includes the name of the substrate and the type of modification which it undergoes in the course of the reaction. Very often it also includes the cofactor and the product of the reaction. Systematic names unambiguously describe an enzyme׳s activity. However very often they are not suitable for everyday use.