1. What is Protein Molarity?

Protein molarity refers to the concentration of a protein solution expressed in moles per liter (M). It's a fundamental measurement in biochemistry that allows researchers to standardize protein concentrations across different experiments and preparations.

2. How Does the Calculator Work?

The calculator uses the protein molarity formula:

Where:

• \( M \) — Protein molarity (μM)
• \( C \) — Protein concentration (mg/mL)
• \( MW \) — Molecular weight (kDa)

Explanation: The formula converts mass concentration (mg/mL) to molar concentration (μM) by dividing by the molecular weight and multiplying by 1000 for unit conversion.

3. Importance of Protein Molarity

Details: Knowing the molar concentration of proteins is essential for:

• Preparing solutions with specific protein:ligand ratios
• Standardizing experiments across different proteins
• Calculating stoichiometry in binding experiments
• Determining enzyme kinetics parameters

4. Using the Calculator

Tips:

• Enter protein concentration in mg/mL
• Enter molecular weight in kDa (kilodaltons)
• For accurate results, use precise measurements of both concentration and molecular weight
• Remember that the molecular weight should be for the specific form of the protein you're working with (monomer, dimer, etc.)

5. Frequently Asked Questions (FAQ)

Q1: Why convert to molarity instead of using mg/mL?
A: Molarity allows comparison between different proteins based on the number of molecules rather than mass, which is more relevant for most biochemical interactions.

Q2: How do I determine my protein's molecular weight?
A: You can calculate it from the amino acid sequence (for recombinant proteins) or measure it using techniques like mass spectrometry.

Q3: What if my protein forms multimers?
A: Use the molecular weight of the active form. For example, if your protein works as a dimer, use twice the monomer molecular weight.

Q4: Why multiply by 1000 in the formula?
A: This converts the result from mM to μM (millimolar to micromolar), which is often a more convenient unit for protein concentrations.

Q5: Can I use this for nucleic acids or other biomolecules?
A: Yes, the same formula works for any molecule when you know its concentration and molecular weight.