Tetranitromethane. A Reagent for the Nitration of Tyrosyl Residues in Proteins^*

Abstract

tions for the nitration reaction and its quantitation have been established by comparison of spectrophotometric results with those obtained by amino acid analyses.

Involvement of tyrosyl residues in the binding of benzodiazepines to their brain receptors

“…We have tested the ability of benzodiazepines and of GABA, which has been reported to interact with the benzodiazepine receptor [3,6], to protect against the TNM effect (table 1) TNM may also modify cysteine or, though less likely, tryptophan residues [7]. Nitration of tyrosine is expected to proceed much slower at pH 6.5 than at pH 8.0, whereas nitration of cysteine is efficient at the lower pH [4,7]. Tryptophan is not expected to react below pH 7 [7].…”

Location of reactive tyrosine residues in trypsin

“…2.4. The nitration of 100 ml of 1% trypsin solution was performed according to Riordan and co-workers [3,4] at room temperature by the addition of 2 ml of the tetranitromethane solution, i.e. of an approximately Cfold molar excess with respect to the number of tyrosine residues.…”

Chemical modifications of the protein of carcinoembryonic antigen: associated changes in immunological activity and conformation

“…Reaction of CEA with tetranitromethane.-A method similar to the one described by Sokolovsky, Riordan and Vallee (1966) was used. Two samples of CEA (8 mg) were dissolved in 1 ml of 0 05M Tris-HCI buffer, pH 8*0, one buffer containing 6M guanidine HCI.…”