Which of the following statements regarding the absorption of UV-light by aromatic amino acids is true?
1
All amino acids absorb visible light, thus are colored substances.
2
Tryptophan and phenylalanine absorb maximum UV-light at a wavelength of 280 nm
3
Absorbance at 280 nm is commonly used for the detection and quantification of purified proteins because of the UV-light absorption by aromatic side chains.
4
Phenylalanine absorbs maximum UV-light at a wavelength of 280 nm