Xanthoproteic acid
Encyclopedia
Xanthoproteic acid is a noncrystallizable yellow substance derived from proteins upon treatment with nitric acid. Nitric acid
reacts with proteins to form yellow nitrated products. This reaction is known as the xanthoproteic reaction
. This test is carried out by adding concentrated nitric acid to the substance being tested, and then heating the mixture. If proteins are present that contains amino acids with aromatic rings, the mixture turns yellow. Upon adding a strong base such as liquid ammonia, the color turns orange. These color changes are caused by nitrated aromatic rings in the protein. Xanthoproteins are formed when the acid contacts epithelial cells and are a certain giveaway of inadequate safety precautions when handling nitric acid.
Nitric acid
Nitric acid , also known as aqua fortis and spirit of nitre, is a highly corrosive and toxic strong acid.Colorless when pure, older samples tend to acquire a yellow cast due to the accumulation of oxides of nitrogen. If the solution contains more than 86% nitric acid, it is referred to as fuming...
reacts with proteins to form yellow nitrated products. This reaction is known as the xanthoproteic reaction
Xanthoproteic reaction
The xanthoproteic test is a method that can be used to determine the amount of protein soluble in a solution, using concentrated nitric acid. The test gives a positive result in those proteins with aminoacids carrying aromatic groups, especially in the presence of tyrosine...
. This test is carried out by adding concentrated nitric acid to the substance being tested, and then heating the mixture. If proteins are present that contains amino acids with aromatic rings, the mixture turns yellow. Upon adding a strong base such as liquid ammonia, the color turns orange. These color changes are caused by nitrated aromatic rings in the protein. Xanthoproteins are formed when the acid contacts epithelial cells and are a certain giveaway of inadequate safety precautions when handling nitric acid.