BIOMOLECULES AND ENZYMES

Detailed explanation-1: -Due to the presence of tyrosine and tryptophan, proteins and peptides containing these aromatic amino acids absorb UV light at a wavelength of 280 nm. Each of these residues has distinct absorption and emission wavelengths and varies in quantum yields.

Detailed explanation-2: -On a molar basis tryptophan absorbs more light at 280nm than either tyrosine or phenylalanine. Note that BSA protein, which has an absorbance value at 230 nm similar to that of tryptophan, has less absorbance at 280 nm as a result of fewer aromatic rings on a molar basis.

Detailed explanation-3: -To different degrees, all aromatic amino acids absorb ultraviolet light. Tyrosine and tryptophan absorb more than do phenylalanine; tryptophan is responsible for most of the absorbance of ultraviolet light (ca. 280 nm) by proteins.

Detailed explanation-4: -Absorption in the range of 230–300 nm is dominated by the aromatic side-chains of tryptophan (Trp), tyrosine (Tyr), and phenylalanine (Phe) residues, and there is weak contribution by disulphide bonds near 260 nm (Goldfarb et al.

Detailed explanation-5: -Aromatic amino acids such as tyrosine and tryptophan absorbs UV light at 280 nm. This is because of the side chain ring structure present in their R group. The Pie electrons undergoes delocalization in the aromatic ring, which helps in the high absorbance of aromatic amino acids.