Tutorial Multidimensional Searching in Biochemical Pathways

The very appearance of figure lOJ-20 - and of the poster Biochemical Pathways as a whole [20] - clearly points out the deficiencies of a two-dimensional medium, a drawing plane, to represent the complexity, the high interconnectivity of biochemical pathways. 

Many of the species involved in the endogenous metabolism can undergo a multitude of transformations, have many reaction channels open, and by the same token, can be produced in many reactions. In other words, biochemical pathways represent a multi-dimensional space that has to be explored with novel techniques to appreciate and elucidate the full scope of this dynamic reaction system. 

The reaction database compiled on Biochemical Pathways can be accessed on the web and can be investigated with the retrieval system C ROL (Compound Access and Retrieval On Line) [211 that provides a variety of powerful search techniques. The Biochemical Pathways database is split into a database of chemical structures and a database of chemical reactions that can be searched independently but which have been provided with efficient crosslinks between these two databases. 

71 reactions were found in which L-glutamate participates, 47 reactions leading to L-glutamatc and 24 reactions starting from L-glutamatc. 

A search for derivatives of L-glutamate can be performed by a substructure search (SSS) (sec Section 6.3). figure 10,3-24b shows the query of the SSS observe that here, too, the stereochemistry can be specified and this is then considered in the SSS. The query provides 25 hits, including L-glutamatc, N-acctylghjtamate, etc. but also compounds such as tctrahydrofolatc, folate, etc. which would never be found by a name search, 

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