BIOLOGY
AMINO ACIDS
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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UV light is absorbed by the backbone of the protein
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UV light is absorbed by the peptide bonds of the protein
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UV light is absorbed by the aromatic amino acids of the protein
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UV light is absorbed by all the non-aromatic amino acids of the protein
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Detailed explanation-1: -Spectrophotometric protein quantification assays are methods that use UV and visible spectroscopy to rapidly determine the concentration of protein, relative to a standard, or using an assigned extinction coefficient.
Detailed explanation-2: -Protein concentration can be estimated by measuring the UV absorbance at 280 nm; proteins show a strong peak here due to absorbance from Tryptophan and Tyrosine residues (commonly referred to as A 280). This can readily be converted into the protein concentration using the Beer-Lambert law (see equation below).
Detailed explanation-3: -Proteins primarily absorb UV light due to the presence of tryptophan, tyrosine, and phenylalanine residues, with absorbance maxima at 280, 275, and 258 nm, respectively.
Detailed explanation-4: -Two amino acids are primarily responsible for the UV absorbance of proteins: tryptophan and tyrosine.