Dimethylaminoazobenzene isothiocyanate

The Edman degradation method for polypeptide sequence determination. The sequence is determined one amino acid at a time, starting from the amino-terminal end of the polypeptide. First the polypeptide is reacted with phenylisothiocyanate to form a polypeptidyl phenylthiocarbamyl derivative. Gentle hydrolysis releases the amino-terminal amino acid as a phenylthiohydantoin (PTH), which can be separated and detected spectrophoto-metrically. The remaining intact polypeptide, shortened by one amino acid, is then ready for further cycles of this procedure. A more sensitive reagent, dimethylaminoazobenzene isothiocyanate, can be used in place of phenylisothiocyanate. The chemistry is the same. 

CAPS, 3-[cyclohexylamino]-l-propanesulfonic acid DABITC, dimethylaminoazobenzene isothiocyanate DABTH, dimethylaminoazobenzene thiohydantoin OPA, o-phthalaldehyde PTC, phenylthiocarbamyl PTH, phenylthiohydantoin PVDF, polyvinylidine difluoride TFA, trifluoroacetic acid... 

Chang, J. Y, Manual micro-sequence analysis of polypeptides using dimethylaminoazobenzene isothiocyanate, Meth. Enzymol., 91, 455-466, 1983. 

B 2. The new reagent 4-W,W-dimethylaminoazobenzene-4 -isothiocyanate (DABITC) is often used for the Edman method of protein sequence analysis. Write a reaction showing this use of the reagent. 

The derivatization of 6-amino-2-methyl-2-heptanol (heptaminol) with 4-N,N -dimethylaminoazobenzene-4 -isothiocyanate was used for the HPLC determination of this amino compound in pharmaceutical preparations [63,64]. Labelling with p-phenylbenzoyl isothiocyanate [65] may also be a good technique for the HPLC determination of amines. 

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