UM-BBD pathway prediction system

The UM-BBD Pathway Prediction System, described in more detail by Hou et al. [24], is similar to CATABOL in that it gives pathways, but is available only on-line 

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The UM-BBD Pathway Prediction System (PPS) is based on a set of approximately 240 metabolic rules. The number is approximate because rules change, are added, or deleted, as knowledge grows, hi general, the rules reflect the transformation of the 60 functional groups contained within the UM-BBD. There is an average of four metabohc rules for each fimctional group. A representative rifle is shown in Fig. 5. 

The UM-BBD-PPS predicts all possible metabolic pathways based on its metabolic rules [10]. The user draws a structure or enters a SMILES (Simplified Molecular Input Line Entry System) string representing the compound of interest. The PPS identifies funcfional groups and matches them to appropriate rules. First-round metabolites are produced. Any first-round metabolite can be selected, and used to match another set of rules. When no metabolic rules are matched, the cycle is stopped. This could indicate a non-metabolizable compound or, in other cases, it is an endpoint metabolite that is a common intermediary compound. 

The UM-BBD-PPS is designed to guide users, rather than offer predictions that appear absolute. This contrasts with the CATABOL prediction system that predicts only one metabolic pathway for a given compound and shows mass balances at any instant in time. While many users would like this precision, it is unlikely that only one pathway operates for most chemicals in nature, or that all environments are identical in biodegradative capability. 

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