The Pauly reaction is a

chemical test In chemistry, a chemical test is a qualitative property, qualitative or Quantitative property, quantitative procedure designed to identify, quantify, or characterise a chemical compound or substituent, chemical group. Purposes Chemical testing m ...

used for detecting the presence of

tyrosine -Tyrosine or tyrosine (symbol Tyr or Y) or 4-hydroxyphenylalanine is one of the 20 standard amino acids that are used by cells to synthesize proteins. It is a non-essential amino acid with a polar side group. The word "tyrosine" is from the Gr ...

histidine Histidine (symbol His or H) is an essential amino acid that is used in the biosynthesis of proteins. It contains an α-amino group (which is in the protonated –NH3+ form under biological conditions), a carboxylic acid group (which is in the de ...

in proteins. It is named after German chemist

Hermann Pauly Hermann Pauly (18 July 1870 – 31 October 1950) was a German chemist and inventor. He is known for the Pauly reaction, a chemical test used for detecting the presence of tyrosine or histidine in proteins. Early years Hermann Pauly was born in ...

, who first described the reaction. When proteins containing either tyrosine or histidine are reacted with diazotized

sulfanilic acid Sulfanilic acid (4-aminobenzenesulfonic acid) is an organic compound with the formula H3NC6H4SO3. It is an off-white solid. It is a zwitterion, which explains its high melting point. It is a common building block in organic chemistry."Sulphanili ...

under alkaline conditions, a red color is formed by a

coupling reaction A coupling reaction in organic chemistry is a general term for a variety of reactions where two fragments are joined together with the aid of a metal catalyst. In one important reaction type, a main group organometallic compound of the type R-M (R = ...

References

Protein methods Biochemistry detection reactions {{analytical-chemistry-stub