| ETA is a new knowledge-based expert system that simulates the biotransformation and metabolism of xenobiotics. By application of a collection of rules which supply knowledge, the program recognizes key functional groups within the complete xenobiotic structure and substitutes them to predict possible metabolites. META employs established methodologies to predict lipophilicity, stability, and reactivity of the metabolites. A comprehensive knowledge base was constructed to model mammalian xenobiotic metabolism with META methodology by consulting experts in medicinal chemistry. Metabolic pathways are often experimentally observed to compete for substrates, which is modeled by the prioritization of the rules. The META-4 algorithm optimizes the prioritization knowledge base development. Another algorithm, called Graphsort, is used to assign a unique name to chemical entities that can be represented by graphs. Uniqueness is accomplished by canonical ordering of the nodes using novel node invariants based on distance distributions.;The... |
