1. What is the DNA Extinction Coefficient?

The extinction coefficient (ε) is a measure of how strongly a chemical species absorbs light at a particular wavelength. For DNA, it represents the sum of the individual extinction coefficients of its constituent nucleotides.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• Adenine (A) — 15,400 M⁻¹cm⁻¹
• Cytosine (C) — 7,400 M⁻¹cm⁻¹
• Guanine (G) — 11,500 M⁻¹cm⁻¹
• Thymine (T) — 8,700 M⁻¹cm⁻¹

Explanation: The calculator sums the extinction coefficients of each nucleotide in the DNA sequence to determine the total extinction coefficient.

3. Importance of Extinction Coefficient Calculation

Details: The extinction coefficient is essential for quantifying DNA concentration using UV spectrophotometry, which is crucial for molecular biology experiments, PCR, sequencing, and other DNA-based techniques.

4. Using the Calculator

Tips: Enter the DNA sequence (A, C, G, T characters only). The calculator will automatically convert input to uppercase and ignore any non-DNA characters.

5. Frequently Asked Questions (FAQ)

Q1: Why are extinction coefficients different for each nucleotide?
A: Each nucleotide has a unique chemical structure that absorbs light differently, resulting in distinct extinction coefficients.

Q2: How accurate is this calculation?
A: The calculation provides an estimate based on standard values. Actual extinction may vary slightly depending on environmental conditions.

Q3: Can I use this for RNA sequences?
A: No, this calculator is specifically for DNA. RNA has different extinction coefficients, particularly for uracil instead of thymine.

Q4: What wavelength is used for DNA extinction coefficient?
A: DNA extinction coefficients are typically measured at 260 nm, which is the absorption maximum for nucleic acids.

Q5: How is the extinction coefficient used in practice?
A: It's used in the Beer-Lambert law (A = εcl) to calculate DNA concentration from absorbance measurements.