Solutions White Papers
Download DocumentNEMA key based exact match searching
Abstract
Registry and retrieval systems require exact structural matches. Such matches have to be performed frequently to confirm novelty for a structure, or assign as a new batch (sample) of an existing substance. Accuracy is of course important for exact structural matches, but the process also needs to be fast. Reliability and speed of searching is greatly simplified if a canonical name can be generated for a structure, and the process is further simplified if that can be machine generated. NEMA (Newly Enhanced Morgan Algorithm) was developed to meet these needs.
The Symyx NEMA project delivered the following important cheminformatics technologies:
- A new generation of stereochemistry perception methodology that also supports nontetrahedral stereochemistry.
- The NEMA key for fast exact structure searching and deduplication. It has no limitation on the sizes of chemical structures. It supports Symyx's enhanced stereochemistry, Rgroups, and star-atoms. This technology is an important new addition to Symyx's gold-standard chemistry.
- New structure similarity searching methods can be built based on NEMA's capability of comprehensive atom-equivalency calculation.
Lipitor and its enantiomer generate the same constitutional key, allowing a query to retrieve both structures, but the stereo keys are unique, and will not find other isomers, allowing fast retrieval of a specific isomer.
To read the complete white paper, click the Download Document link near the top of the this article.
