Protein Solubility Calculator

Predict protein solubility patterns using either the Cohn salting-out model or pH-dependent isoelectric precipitation curves.

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Input Parameters

Enter details for calculation.

Estimated Protein Solubility

10.0 mg/mL
Solubility calculated using selected model equations.
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Expert Tip

Salting-out is common for purification. At low salt concentrations (salting-in), solubility increases; at high ionic strength (salting-out), water molecules are sequestered, causing proteins to aggregate.

Calculation Methodology & Details

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Formula

Cohn model: log₁₀(S) = β - K_s × [Salt] pH curve: S = S_min × (1 + k(pH - pI)²)

Cohn model describes salting-out. The pH model approximates isoelectric precipitation: solubility decreases parabolically as pH approaches the isoelectric point.

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Important Disclaimer

The calculations provided are for educational and general planning guidelines only. They do not replace professional laboratory or environmental analysis or certified scientific advice.

How to Predict Solubility

Steps to estimate protein solubility:

1

Select Model

Choose between Cohn salting-out (salt-dependent) or isoelectric precipitation (pH-dependent).

2

Set constants

Provide reference solubility at zero salt (β) or minimum solubility at pI.

3

Observe output

Vary salt or pH to calculate the estimated solubility in mg/mL.

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