pKa (PhysChem Suite™)
Acid Dissociation Calculator
Predict pKa (acid dissociation and ionization) values for organic molecules from chemical structure.
Trusted By Companies Worldwide
Explore
Accurately predict acid dissociation constants directly from structure.
Use the pKa module to:
Calculate pKa for organic compounds under standard conditions.
Visualize all ionizable centers in your compound.
Plot the distribution of all ionized microspecies as a function of pH.
Train the algorithm with your own experimental data.
Benefits
Everything You Need in a pKa Calculator
Accurate, Reliable Predictions
- Predictions are based on a database of more than 26,000 compounds, continuously expanded to improve accuracy.
- Evaluate prediction confidence using a reliability index, similar structures, and literature references for the original experimental data.
- Combine results from two complementary prediction algorithms in a single application.
Gain Deeper Insight into Ionization
- Assess the distribution of ionized states and microspecies from a variety of plots.
- Understand molecular behavior with automatically generated plots of pKa versus pH.
- Identify trends and prioritize compounds using scatter plots, filtering, sorting, and ranking tools.
- Easily identify ionizable groups with color-mapping.
Improve Predictions with Machine Learning
- Get the accuracy of an in-house model from a commercial platform by training with your own experimental pKa data.
- Expand the applicability domain into proprietary chemical space using project-specific data.
- Build curated training sets for each project to achieve fine-tuned prediction accuracy.
Physicochemical property predictions you can trust
pKa FAQs
pKa describes how readily a molecule donates or accepts a proton at its ionization sites. It provides a standard way to compare ionization behavior across chemically diverse compounds. pKa is important because it determines the ionization state of a molecule at a given pH, directly influencing key properties such as solubility, permeability, absorption, distribution, and overall ADMET behavior.
The pKa Classic model is trained on more than 26,000 compounds and over 42,000 experimental pKa values. pKa predictions use multiple complementary algorithms and advanced similarity-based approaches to improve reliability across diverse chemical space.
Our pKa prediction modules are continuously refined to improve accuracy and expand chemical space coverage. Prediction accuracy depends on chemical class and applicability domain and can be further improved by training supported models with high-quality proprietary experimental data.
Classic Algorithm:
- The internal training database is made up of more than 26,000 compounds, representing more than 42,000 pKa values.
- Uses Hammett-type equations for popular ionizable functional groups and carefully derived electronic substituent constants (σ) are used to predict pKa values.
- Accounts for tautomeric equilibria, covalent hydration, resonance effects, and α, β-unsaturated systems.
GALAS Algorithm:
- The internal training set contains more than 17,500 compounds representing more than 20,000 ionization centers.
- A database of ionization centers, interaction constants, and interaction calculation methods are used to simulate complete distribution plots and produce a full range of protonation states across different pH conditions.
- Generates full pH-dependent behavior of molecules.
- Provides outputs including pH-dependent net molecular charge, protonation state distributions, and average charge per ionization center
pKa (the acid dissociation constant) describes the inherent tendency of a compound or ionizable functional group to lose H+ and generate hydronium ions (H3O+).
pH measures the concentration of hydronium ions [H3O+] in aqueous solution.
pH=−log[H3O+]
Ready to take the next step?
Beyond pKa Prediction
Explore the wider Percepta Platform for additional molecular property predictions.
Talk to our team
Schedule a consultation with our experts to discuss your workflow, requirements, and implementation needs
Stay up to date
Stay up-to-date on all the latest insights, research and product news from Revvity Signals.
