High impact information on thionitrobenzoic acid

• Reaction of the native protein with 5,5'-dithiobis (2-nitrobenzoic acid) resulted in the release of 30 mol of the product 5-mercapto-2-nitrobenzoate, and the loss of the RNase inhibitory activity [1].
• Tryptophan fluorescence is also examined during the release of the thionitrobenzoate [2].
• Seven intra-molecular distances (R(DA)) under unfolding conditions were estimated from measurements of time-resolved fluorescence resonance energy transfer between the donor Trp53 and the non-fluorescent acceptor TNB coupled to one of the seven cysteine side-chains [3].
• Subunit III Cys-115 of beef heart cytochrome c oxidase cross-links by disulphide bond formation to thionitrobenzoate-modified yeast cytochrome c, a derivative shown to bind into the high-affinity site for substrate [Fuller, Darley-Usmar and Capaldi (1981) Biochemistry 20, 7046-7053] [4].
• The light-sensitive species is apparently the DTNB, because a spectral-irradiation experiment showed that the wavelength of light that produced the maximum rate of absorbance change coincided with the peak absorbance of DTNB, and it was well separated from the thionitrobenzoate absorbance peak [5].

Biological context of thionitrobenzoic acid

• Replacing the thionitrobenzoate (Nbs) moiety from Cys71 with cyanide resulted in a gradual recovery of the enzyme activity, which indicates that a steric hindrance at the active site was introduced by Nbs but removed by cyanide [6].
• Full medium exposed to HOCl for 24 h would support methionine noninhibitable apoptosis, but did not react with 2-nitro-5-thiobenzoic acid (TNB), raising the possibility that the final inducer is a nonoxidant formed from HOCl and chloramines [7].
• The modified enzyme is protected from alkylation by iodoacetate until thionitrobenzoate is removed [8].

Anatomical context of thionitrobenzoic acid

• Use of thionitrobenzoic acid to characterize the stability of nitric oxide in aqueous solutions and in porcine aortic endothelial cell suspensions [9].
• In this work it has been observed that human blood plasma is able to catalyse the reaction between tert.butyl hydroperoxide and 2-nitro-5-mercaptobenzoic acid [10].

Associations of thionitrobenzoic acid with other chemical compounds

• Measurements of activity were made both before and after treatment with an excess of beta-mercaptoethanol to remove the blocking thionitrobenzoate moieties [11].
• Cyanate present in the dried residue of acetone-deproteinized plasma is converted to a chromophoric thiocarbamyl derivative by addition of pH 3.0-buffered thionitrobenzoic acid [12].
• A rapid assay for catechol oxidase and lactase using 2-nitro-5-thiobenzoic acid [13].

Gene context of thionitrobenzoic acid

• 5,5'-Dithiobis(2-nitrobenzoate) (DTNB) is reduced in mitochondrial suspensions to 5-mercapto-2-nitrobenzoate (MNB) by 3-hydroxybutyrate and isocitrate [14].
• When the release of 2-nitro-5-mercaptobenzoic acid was measured, 3 mol of sulfhydryl residues was found to be modified per mole of the enzyme by DTNB [15].
• The resulting enzyme derivative has 1.6 moles of thionitrobenzoate/mole of enzyme bound to sulfhydryl groups of rhodanese [16].

Analytical, diagnostic and therapeutic context of thionitrobenzoic acid

• A unique peptide, containing the thionitrobenzoate adduct, was isolated via reverse phase HPLC following digestion with endoproteinase Glu-C [17].
• Proteolysis and isolation of the labeled peptides using reverse phase HPLC and subsequent Edman sequence analysis detected and identified the thionitrobenzoate adducts of each of the three cysteinyl peptides of chloroperoxidase [17].

References