Enter the A280 and the A260 into the Calculator. The calculator will evaluate the Protein from Layne Equation. 

Protein from Layne Equation Formula

P = 1.55*A280 -.76*A260


  • P is the Protein concentration from Layne Equation ((mg/mL))
  • A280 is the A280
  • A260 is the A260

To calculate Protein concentration from Layne Equation,

How to Calculate Protein from Layne Equation?

The following steps outline how to calculate the Protein from Layne Equation.

  1. First, determine the A280. 
  2. Next, determine the A260. 
  3. Next, gather the formula from above = P = 1.55*A280 -.76*A260.
  4. Finally, calculate the Protein from Layne Equation.
  5. After inserting the variables and calculating the result, check your answer with the calculator above.

Example Problem : 

Use the following variables as an example problem to test your knowledge.

A280 = 7

A260 = 6


What is the significance of A280 and A260 in protein concentration measurement?

A280 and A260 are measurements of absorbance at 280 nm and 260 nm wavelengths, respectively. A280 is used to estimate protein concentration because proteins absorb UV light at 280 nm due to the presence of aromatic amino acids. A260, on the other hand, is often used to measure nucleic acid concentration. The ratio of A280 to A260 can help differentiate between protein and nucleic acid in a sample.

How accurate is the Layne Equation for determining protein concentration?

The Layne Equation provides an estimate of protein concentration based on UV absorbance measurements. While it is a widely used method, its accuracy can be influenced by the presence of other absorbing substances in the sample, the purity of the protein, and the specific amino acid composition of the protein. It is considered a reliable method for relatively pure protein solutions.

Can the Layne Equation be used for all types of proteins?

The Layne Equation is generally applicable to a wide range of proteins, given that most proteins contain aromatic amino acids that absorb at 280 nm. However, the equation might not be as accurate for proteins with low levels of these aromatic amino acids or for proteins that have significant amounts of absorbing contaminants. In such cases, alternative methods or additional purification steps may be necessary.

Is there a need for calibration or standards when using the Layne Equation?

While the Layne Equation provides an estimate of protein concentration based on direct measurements of A280 and A260, the use of calibration standards can improve accuracy. These standards, typically solutions of known protein concentrations, can help account for variations in the measurement setup, such as differences in the spectrophotometer. Calibration with standards is recommended especially when precise quantification is necessary.