UV-Vis spectroscopic measurements consist one of the most widely used methods for protein quantification. This is due to the fact that the tryptophan and tyrosine (and to a lesser extent the phenylalanine) residues of proteins strongly absorb at 280 nm. Hence, the corresponding absorbance is used for the calculation of protein concentration, based on specific quantification formulas. If the protein sample does not have tryptophan or tyrosine, the concentration can still be easily measured by the absorption at 205 nm in which the peptide bonds are analysed directly (Scopes method). Conformational studies can also be performed under special conditions.
The Hitachi's U-5100 UV-Visible Spectrophotometer is a general-purpose instrument for absorption spectroscopy in the ultraviolet, visible, and near infrared spectral regions. It delivers a compact, lightweight package with remarkable power savings and a long life for its light source. The optical scheme consists of a Seya-Namioka mount monochromator configuration and the useable wavelength range is 190-1100 nm with temperature control. UV-Vis spectroscopic services are mainly focused towards protein quantification and concentration determination. Moreover, It contains automatic switching of 6 cells by using an automatic 6-cell turret and a high-speed scanning (12,000 nm/min) deliver a substantial reduction in measurement time (approximately 60% reduction).