Protein Extinction Coefficient Calculator
Calculate molar extinction coefficient at 280nm
Protein Sequence
Chromophore Count
Tryptophan (W)1 (ε = 5,500)
Tyrosine (Y)2 (ε = 1,490)
Cysteine (C)0
Max Disulfide Bonds0 (ε = 125 each)
Extinction Coefficient (ε₂₈₀)
8,480
M⁻¹ cm⁻¹
Extinction Coefficients
All Cys reduced8,480 M⁻¹cm⁻¹
With 0 S-S bonds8,480 M⁻¹cm⁻¹
All Cys oxidized8,480 M⁻¹cm⁻¹
Absorbance Values
Abs 0.1% (1 g/L) reduced15.116
Abs 0.1% with S-S15.116
A280 per 1 mg/mL1.512
Estimated MW5.6 kDa
Concentration Formula
C (M) = A280 / ε × path length
Using ε = 8,480 M⁻¹cm⁻¹
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Editorial Note
MyCalcBuddy Editorial Team
This page is maintained as an educational calculator reference.
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Formula Source: Standard Mathematical References
by Various
🔄Last reviewed: May 2026
✓Formula checks are based on standard references and internal QA review.