Direct Determination Of Saliva Proteins Lab Report
2.4.4. Direct determination of saliva proteins
Protein contaminated with nucleic acids absorbed the light at wavelength 280 nm and it absorbs much strongly at wavelength 205 nm when it is free from nucleic acids. The UV-visible spectrophotometer was used in determination of saliva proteins (Figure 2.2). Cold trichloroacetic acid (10 % w/v ) was added to the sample, centrifuged for 10 minutes to precipitate protein. The absorbance of a known volume ( 50 µl) of sample diluted with 4 milliliters distil water was measured at wavelengths 205 nm , 260 and 280 nm for each subject and patient . The concentrations of contaminated and uncontaminated proteins were determined by using the following equations (Layne, 1957; Scopes, 1974; Stoscheck, 1990):
Protein contaminated with nucleic acids absorbed the light at wavelength 280 nm and it absorbs much strongly at wavelength 205 nm when it is free from nucleic acids. The UV-visible spectrophotometer was used in determination of saliva proteins (Figure 2.2). Cold trichloroacetic acid (10 % w/v ) was added to the sample, centrifuged for 10 minutes to precipitate protein. The absorbance of a known volume ( 50 µl) of sample diluted with 4 milliliters distil water was measured at wavelengths 205 nm , 260 and 280 nm for each subject and patient . The concentrations of contaminated and uncontaminated proteins were determined by using the following equations (Layne, 1957; Scopes, 1974; Stoscheck, 1990):