Pauly reaction

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The Pauly reaction (also: Pauly sample, also: Pauly's diazo reaction) is used for the qualitative detection of the amino acids tyrosine and histidine . It is named after its discoverer Hermann Pauly (1870–1950).

reaction

Tyrosine and histidine have an aromatic ring on which electrophilic substitutions can easily take place. Diazotized sulfanilic acid couples with the aromatic ring to form a red azo dye .

Pauly reaction equation

In the first step, sulfanilic acid is diazotized by adding sodium nitrite in the presence of hydrochloric acid . After the addition to the amino acid solution, the mixture is made alkaline and, in the presence of aromatic groups, the azo dyes are formed , e.g. B. azotyrosine and azohistidine.

With a variant of the Pauly reaction, histamine can be quantified photometrically .

history

The Pauly reaction was described by Hermann Pauly in 1904.

Web links

Individual evidence

  1. Student assignment: CHEMKON 3/2018 . In: CHEMKON . tape 25 , no. 3 , June 2018, p. 121–122 , doi : 10.1002 / ckon.201880371 .
  2. RK Marwaha, BF Johnson, GE Wright: Simple stability-indicating assay for histamine solutions. In: American journal of hospital pharmacy. Volume 42, Number 7, July 1985, pp. 1568-1571, PMID 4025356 .
  3. Hermann Pauly: About the constitution of the histidine. I. Communication. In: Z. Physiol. Chem. (Hoppe-Seyler) (1904), Vol. 42, pp. 508-518. doi: 10.1515 / bchm2.1904.42.5-6.508
  4. ^ Hermann Pauly, In: Hoppe-Seyler's Z. Physiol. Chem. (1915), Vol. 94, p. 288.