Two standard methods are used to express the relation between protein concentration and its absorbance at 280 nm. One of these m
ethods is called molar extinction coefficient and the other is called specific extinction coefficient (or E1%1cm). The molar extinction coefficient is the theoretical absorbance of a protein solution whose concentration is one molar. The specific extinction coefficient is the absorbance of a protein solution whose concentration is 1g% (or 10 mg/ml). (i) You measure the absorbance of a standard BSA solution (concentration 0.60 mg/ml) at 280 nm and find it to be 0.402. What is specific extinction coefficient and molar extinction coefficient of BSA (assume that the molecular weight of BSA is 70,000).