Common Substructures Identification

A substructure search algorithm is usually the first step in the implementation of other important topological procedures for the analysis of chemical structures such as identification of equivalent atoms, determination of maximal common substructure, ring detection, calculation of topological indices, etc. 

Carr et al., 1993). The neutral loss scan mode is used as a class identifier to also screen components that contain a common substructure. Barbuch et al. demonstrated this approach for the class identification of phytoestrogens (Barbuch et al., 1989), using thermospray ionization (TSI)-LC/MS/MS. Brownsill et al. used a similar electrospray ionization (ESI)-LC/MS/MS approach for the analysis of metabolites in rat liver slices (Brownsill et al., 1994). 

Brint, A.T. and Willett, P. (1987a). Algorithms for the Identification of Three-Dimensional Maximal Common Substructures. J.Chem.Inf.Comput.ScL, 27,152-158. 

Cone, M.M., Venkataraghavan, R. and McLafferty, F.W. (1977). Molecular Structure Comparison Program for the Identification of Maximal Common Substructures. JAm.Chem.Soc., 99, 7668-7671. 

As previously noted, the MCSS problem for general structures is usually very complicated to solve. For the two given structures containing m and n atoms, respectively, the maximal number of possible atom-by-atom comparisons for the identification of all common substructures containing k atoms is [55] ... 

Cone MM, Venkataraghavan R, McLafferty FW. Molecular structure comparison program for the identification of maximal common substructures. J Am Chem Soc 1977 99 7668-7671. 

Brint AT, Willett P. Algorithms for the identification of three-dimensional maximal common substructures. J Chem Inf Comput Sci 1987 27 152-158. 

Yuan S, Zheng C, Zhao X, Zeng F. Identification of maximal common substructures in structure/activity studies. Anal Chim Acta 1990 235 239-241. 

In qualitative read-across the potential of a chemical to exhibit a property is inferred from the established potential of one or more analogues. The analogue approach could simply be regarded as the use of SAR. The process involves (1) the identification of a chemical substructure that is common to two substances (which are considered to be analogues) and (2) the assumption that the presence (or absence) of a property/activity for a substance can be inferred from the presence (or absence) of the same property/activity for the analogous substance. 

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