# \[ANN\] eQuilibrator.jl - an interface to equilibrator\_api

**URL:** https://discourse.julialang.org/t/ann-equilibrator-jl-an-interface-to-equilibrator-api/62946
**Category:** Package Announcements
**Created:** [June 15, 2021, 12:43pm UTC](https://discourse.julialang.org/t/ann-equilibrator-jl-an-interface-to-equilibrator-api/62946 "2021-06-15T12:43:28Z")
**Posts on this page:** 1
**Page:** 1

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### Author: ![Elmo](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/elmo/32/17979_2.png) [@Elmo](https://discourse.julialang.org/u/Elmo)
#### Post date: [June 15, 2021, 12:43pm UTC](https://discourse.julialang.org/t/ann-equilibrator-jl-an-interface-to-equilibrator-api/62946/1 "2021-06-15T12:43:29Z")

</div>

Thermodynamic data is useful for constraining the direction and rate of chemical reactions. Gibbs free energy is often used to analyze biological systems, and large databases exist to calculate the Gibbs free energy of reactions. Two useful resources for this include the [eQuilibrator](https://equilibrator.weizmann.ac.il/) website and the associated Python package [equilibrator-api](https://equilibrator.readthedocs.io/en/latest/). I have written a Julia interface to the Python package, called [eQuilibrator.jl](https://github.com/stelmo/eQuilibrator.jl). A quick example is shown below:

```julia
using eQuilibrator
using Unitful

system = eQuilibrator.System(ionic_strength=150.0u"mM")

rxn_string = bigg"atp + h2o = adp + pi"

dg_prime(system, rxn_string) # -26.88 ± 0.3 kJ mol^-1

```

The hope is that this functionality can be combined with other Julia-based biological modeling packages, e.g. [COBREXA](https://github.com/LCSB-BioCore/COBREXA.jl) for constraint-based analysis.

Feel free to ask questions/offer suggestions etc. 🙂