How to Name Atoms in Phosphates, Polyphosphates, their Analogues, etc.

Provisional Recommendations are drafts of IUPAC recommendations on terminology, nomenclature, and symbols, made widely available to allow interested parties to comment before the recommendations are finally revised and published in IUPAC’s journal Pure and Applied Chemistry. 

Procedures are proposed for the naming of individual atoms, N, P, O, etc., in phosphate esters, amidates, thiophosphates, polyphosphates, their mimics, and analogues of transition states for enzyme-catalysed phosphoryl transfer reactions. Their purpose is to enable scientists in very different fields, e.g. biochemistry, biophysics, chemistry, computational chemistry, crystallography, molecular biology, NMR, etc. to share standard protocols for the labelling of individual atoms in complex molecules. This will facilitate clear and unambiguous descriptions of structural results and scientific intercommunication concerning them. At the present time, perusal of the Protein Data Bank (PDB) and other sources shows that there is a limited degree of commonality in nomenclature but a large measure of irregularity in more complex structures. There appears to be no common ground with nomenclature used in computational work or in NMR. The recommendations described herein adhere to established practice as closely as possible, in particular to IUPAC and IUBMB recommendations and to “best practice” in the PDB, especially to its atom labelling of amino acids, and particularly to Cahn-Ingold-Prelog rules for stereochemical nomenclature. They are designed to work in complex enzyme sites for binding phosphates but also to have utility for non-enzymatic systems. Above all, the recommendations are designed to be clear to assimilate and convenient to use.

Comments by 30 June 2016

G. Michael Blackburn <>

See project 2013-039-2-300 to access full text.

See Provisional Recommendations currently under review.