TNBS, 2,4,6-trinitrobenzenesulfonic acid

Other tests for the detection of amino functionalities on solid supports include the TNBS (2,4,6-trinitrobenzenesulfonic acid, picrylsulfonic acid) [Hancock and Battersby Anal Biochem 71 260 ]976], the DABITC [Shah et al. Anal. Commun. 34 325 7997] and the NF31 [Madder et al. Eur J Org Chem 2787 7999] tests. 

Abbreviations used TNBS = 2,4,6-trinitrobenzenesulfonic acid DTNB = 5,5 -dithiobis-(2-nitrobenzoic acid) 2-PDS = 2,2 -dipyridyl disulfide 4-PDS = 4,4 -dipyridyl disulfide CMB = p-chloromercuribenzoic acid. 

TMCS trimethylchlorosilane imidazole TMG tetramethylguanidine TMP 1,1,3,3-tetramethoxypropane TMS trimethylsilyl TNBS trinitrobenzenesulfonic acid TOCSY total correlation spectroscopy TPA texture profile analysis TPCK Af-tosyl-L-phenylalanine chloromethyl ketone... 

The extent of succinylation and acetylation was determined by the trinitrobenzenesulfonic acid (TNBS) method as described by Hall et al. (31) Protein (5 mg) isolated from chemically modified and control soy flour in 0.8 ml of aqueous solution was added to 1 ml of 4% NaHCOg, followed by addition of 0.2 ml of 2,4,6-trinitrobenzenesulfonic acid (12.5 mg/ml). The reaction mixture was incubated at 4O C for 2 hr, and 3.5 ml of 36% HCl was added. The tubes were stoppered and kept at 110 C for 4 hr. After cooling to room temperature (24 C), volume of solution was made up to 10 ml with distilled water, and contents were extracted twice with anhydrous diethyl ether. 

Trinitrobenzenesulfonic acid hydrate (TNBS) reacts with amino acids, yielding a yellow product (Fig. B2.2.3) whose absorbance is measured at 340 nm. TNBS reacts only with amino groups in their unprotonated state. TNBS binds to amino acids in two steps (1) a fast reaction with low affinity, and (2) a slow reaction with relatively high affinity. For practical purposes, the two-step reaction should be considered as one. TNBS reacts with primary amines under slightly alkaline conditions, and lowering the pH stops the reaction. 

Several early workers reported the availability of lysine in breads (4, J 0, 21 ). Palamidis and Markakis (12) reported that the total lysine content decreased with baking or toasting. Available lysine contents significantly decreased as the heat exposure increased. This correlates highly with PER. However, existing techniques, such as fluorodinitrobenzene (FDNB) (2J ) and trinitrobenzenesulfonic acid (TNBS) 22), for chemically determining available lysine suffer interferences and inaccuracies. 

The TNBS-method (TriNitroBenzeneSulfonic acid) was used to determine the content of "free amino groups" in the sample solutions. The samples from the reaction mixture were diluted with a phosphate buffer (0.01 M pH-8), so that a glycine concentration was obtained in the order of 1.10 g.1 1. 

Fig. 3. Summary of key experiments examining transbilayer lipid movement in liposomes. Reaction of dithio-bisnitrobenzoic acid (DTNBA) with R-SH gives R-S-SNBA. Each of the experiments was specifically designed to initially sample only the outer leaflet of the bilayer and then at subsequent periods detect the movement of lipid from the inner to the outer leaflet of the bilayer. lAA, isethionylacetimidate TNBS, trinitrobenzenesulfonate DG, diacylglycerol DTNBA, dithiobisnitrobenzoic acid (Ellman s reagent).

When supramolecular polymers are treated with bulky stopper groups, they may form poly[2]rotaxane daisy chains [45-53]. Harada et al. [31] treated 6-p-aminoCiO-a-CD (40 mM) with 2M excess 2,4,6-trinitrobenzenesulfonic acid sodium salt (TNBS) as bulky stoppers in aqueous solutions. The resulting precipitate was found to be mainly a cyclic trimer by H NMR and TOF mass spectra. After purification of the crude product, the 2D ROESY spectrum of the cyclic trimer shows cross-peaks between phenyl protons close to an amino group and secondary hydroxyl groups (0(2)H). A trinitrophenyl group is found at the secondary hydroxyl group side. A proposed structure of a cyclic trimer (cyclic daisy chain) is shown in Fig. 3.12. Kaneda et al. [38] reported the preparation of cyclic di[2]rota-xane fashion constructed tail-to-tail by azobenzene derivatives of permethylated a-CDs and showed its computer-generated supramolecular structures (Fig. 3.13). Easton et al. [39] also reported the preparation of cyclic di[2]rotaxane constructed by stilbene-appended a-CDs in tail-to-tail fashion (Fig. 3.14). Kaneda et al. [40]... 

Miscellaneous chemicals 2,3,6-trinitrobenzenesulfonic acid (TNBS) and sodium bicarbonate (NaHCOj). 

The amount of amino groups using a trinitrobenzenesulfonic acid (TNBS, Sigma, USA) assay". ... 

We have examined the immunosuppressive effect of IL-2-toxin in a murine DTH model. BALB/c mice were immunized by subcutaneous injection of the hapten trinitrobenzenesulfonic acid (TNBS). Seven days following immunization, mice were challenged with a 25 pi injection of TNBS into the right footpad. After 24 hr, bilateral footpad thickness was measured with a micrometer in order to assess the degree of the immune response. DTH units were defined as differences of 0.01 mm in the thickness between the injected and the non-injected footpad of each animal. Phosphate buffered saline (25 pi) was injected into the footpads of... 

TNBS Method Here, the protease catalyzes dimethylcasein hydrolysis under controlled conditions (e.g., 50°C and pH 9.0). 2,4,6-Trinitrobenzenesulfonic acid (TNBS) is later added to the solution. It reacts with the amino groups of amino adds released during the reaction, forming a colored derivative. The color intensity of the solution is proportional to the amount of amino acid generated by the digestion, hence to the enzyme activity. The absorbance of the protease solution is converted into protease activity by using a standard curve drawn with an enzyme of known activity. The method is time-consuming. 

Trinitrobenzenesulfonic (TNBS) acid hydrate, for degree of protein hydrolysis, 144-146 Triolein, lipid oxidation, 536 Tristearin, lipid oxidation, 536 Tryptophan... 

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