"By the late 1950's it had become evident that the nomenclature of enzymology, in the absence of any guiding authority, in a period when the number of known enzymes was increasing rapidly, was getting out of hand. The naming of enzymes by individual workers had proved far from satisfactory in practice. In many cases the same enzymes became known by several different names, while conversely the same name was sometimes given to different enzymes. Many of the names conveyed little or no idea of the nature of the reactions catalysed, and similar names were sometimes given to enzymes of quite different types. To meet this situation, various attempts to bring order into the general nomenclature of enzymes, or into that of particular groups of enzymes, were made by individuals or small groups of specialists, but none of the resulting nomenclatures met with general approval. (...) The Enzyme List in the sixth edition (1992) contains 3540 entries, of which 178 record enzymes which are now transferred elsewhere in the list, and 166 have been deleted completely. Thus the number of enzymes actually listed is 3196, an increase of 29% on the 1984 edition."