Isozymes nomenclature

Summary of the gene nomenclature, accession numbers, common names, tissue distribution, and function, if known, for the human and mouse alkaline phosphatase isozymes... 

Aldehyde dehydrogenases [AEDHs alde-hyde NAD(P) oxidoreductases EC 1.2.1.3 and EC 1.2.1.51 exist in multiple forms in the cytosol, mitochondria, and microsomes of various mammalian tissues. It has been proposed that AEDHs form a superfamily of related enzymes consisting of class 1 AEDHs (cytosolic), class 2 AEDHs (mitochondrial), and class 3 AEDHs (tumor-associated and other isozymes). In all three major classes, constitutive and inducible isozymes exist. In a proposed nomenclature system, the human AEDHs are designated as lAl, 1A6, IBl, 2, 3A1, 3A2, 3B1, 3B2, 4A1, 5A1, 6A1, 7A1, 8A1, and 9A1 (33-35). 

Different, sometimes confusing and overlapping, nomenclatures for the NOS isozymes are currently being used by the scientific community. Table I lists the different nomenclatures, including a brief definition of the NOS... 

Initially, the concept of isoenzymes had only an operational character (Markert, 1968). Isoenzymes (isozymes) were considered to be any multiple fraction of the same enzyme (Shaw, 1969 Serov, 1968). But later, with the collection of various experimental data, this concept acquired a genetic meaning, and after this the concept of isozymes was given to the genetically determined variants of the same enzyme in the same organisms, as characterized by their similar substrate specificity. The Nomenclature of Multiple Forms of Enzymes, 1971) Enzyme fractions which were not genetically determined were termed multiple forms of enzymes. 

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