A Metabolic Reaction Balancing Web Service for Computational Systems Biology

Background In metabolic network reconstruction the stoichiometric balancing of reactions is essential to create realistic constraint-based models. At the genome scale, balancing is a repetitive task that consumes valuable curator resource that could be deployed elsewhere. Automatic reaction balancing is possible and could be useful across computational systems biology, but widespread use of the appropriate code has been limited by the diversity of non-interoperable programming languages used in the field. RESTful web services offer a language-agnostic way of binding services together. Results Reaction balancing can be posed as a mixed integer linear programming problem to identify stoichiometric coefficients and infer commonly missing components. This functionality has been exposed as a web service that consumes a list of reactions as JSON or SBML. The reaction balancing web service has been deployed at http://www.nactem.ac.uk/balancer . Code is available via Github. By way of demonstration the service has been applied to a Chinese hamster ovary cell metabolic reconstruction to bring a further 219 reactions into balance. Conclusions The majority of systems biology software cannot access existing automatic reaction balancing tools due to a lack of language-specific bindings. Web services bridge different languages by using widely-spoken web communication protocols, meaning that one binding works for almost all languages. Automatic reaction balancing can now be consumed by any systems biology software via a RESTful web service.