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4.2.6 Absorption of ultraviolet light
Aromatic amino acids such as phenylalanine, tyrosine and tryptophan absorb in the UV range of the spectrum with absorption maxima at 200-230nm and 250-290 nm. Dissociation of the phenolic -OH group of tyrosine shifts the absorption curve by about 20nm towards longer wavelength.
Absorption readings at 280nm are used for the quantitative determination of proteins and peptides. Histidine, cysteine and methionine absorb between 200 and 210 nm. |
Last modified: Tuesday, 24 January 2012, 11:05 AM