Disease relevance of DTNB

• Likewise, L-cysteine induces mechanical DTNB-sensitive hyperalgesia in peripheral receptive fields [1].
• However, the cell-surface thiol-reactive reagent 5, 5'-dithiobis(2-nitrobenzoic acid) (DTNB) had a much stronger inhibitory effect in our system, suggesting that cell-surface thiol-containing molecules other than PDI, acting alone or in concert, have a greater effect than PDI on HIV-1 Env-mediated fusion [2].
• The K(M) values were 4.5 microM for NADPH, 480 microM for DTNB and 36 microM for Escherichia coli thioredoxin, the turnover number with DTNB being approximately 40 s(-1) [3].
• Porphyrin photosensitization of proteins in cell membranes as studied by spin-labelling and by quantification of DTNB-reactive SH-groups [4].
• Although unaffected by pertussis toxin, sulfite-triggered PMN adhesion was abrogated by pretreating cells with the membrane-impermeant sulfhydryl reagent 5,5'-dithiobis(2-nitrobenzoic acid) (DTNB), a modifier of thiol groups on the cell surface [5].

High impact information on DTNB

• Contrary to expectations, however, we found that when compared to matched, nonpsychiatric controls, 73-93% of cases in two schizophrenia populations displayed presynaptic dysbindin-1 reductions averaging 18-42% (P = 0.027-0.0001) at hippocampal formation sites lacking neuronal dystrobrevin (i.e., beta-dystrobrevin) [6].
• DTNB alone and in combination with mibefradil induces thermal analgesia [1].
• Isolation and chemical analysis of the DTNB-treated GIF derivative revealed that binding the 5-thio-2-nitrobenzoic acid group with Cys-60 was responsible for the generation of the highly bioactive derivative [7].
• NMDA-activated currents were recorded under control conditions and in the presence of a thiol reductant (DTT), an oxidant (5, 5'-dithio-bis[2-nitrobenzoic acid], DTNB), or the noncompetitive antagonist CP101,606 (CP) [8].
• The classical inhibitor of LCAT activity, 5,5'-dithiobis(2-nitrobenzoic acid) (DTNB), which strongly (89%) inhibited the native enzyme, had partial (45%) inhibitory activity with mutant enzyme species containing a single -SH residue, while the double mutant was not significantly inhibited by DTNB [9].

Chemical compound and disease context of DTNB

• This hyperalgesia is blocked by the oxidizing agent 5,5'-dithio-bis-(2-nitrobenzoic acid) (DTNB) and the T channel antagonist mibefradil [1].
• Melanoma metastases from four different patients who were treated with Fotemustine could be labelled with radioactive drug only under reducing conditions with NADPH as electron donor and DTNB as substrate [10].

Biological context of DTNB

• These data are interpreted to suggest that Cys-31 and Cys-184 are vicinal both to each other and to the "interfacial binding site" at residues 177-182, and that DTNB exerts its effect by steric inhibition [9].
• Both HDL cholesterol esterification and particle enlargement were abolished completely by the LCAT inhibitor DTNB and by heat inactivation of the purified normal LCAT [11].
• Preincubation of these IDL with normal plasma in the absence of 5,5'-dithiobis-(2-nitrobenzoic acid) (DTNB) increased the rate of hydrolysis, in the presence of DTNB, this increment was not observed [12].
• Here, we identify a human gene on chromosome 2p22-23 that encodes a novel protein, beta-dystrobrevin, with significant homology to the other known dystrobrevin (now termed alpha-dystrobrevin) [13].
• Dependence of retina cell aggregation on disulfide exchange activity was shown by blocking that activity with the inhibitor, DTNB, or with a recombinant human PDI with the -WCGHC- motif cysteines mutated [14].

Anatomical context of DTNB

• We incubated labeled 17beta-estradiol with ovarian follicular fluid and with plasma in the absence and presence of the LCAT inhibitor DTNB [15].
• The patient's fibroblasts were also deficient when assayed by the hydroxamate and kinetic assays, but not when tested by the DTNB (5,5'-dithiobis-[nitrobenzoic acid]) method [16].
• Direct assay of protein thiols by reaction with 5,5'-dithiobis-(2-nitrobenzoic acid) (DTNB; Ellman's reagent), suggests that protein disulfides may be the natural electron acceptors for NADH oxidation by the plasma membrane vesicles [17].
• Up and down changes of the glutamate uptake currents in response to treatment with dithiothreitol and 5,5'-dithio-bis-(2-nitrobenzoic) acid (DTNB) were observed in oocytes clamped at -60 mV [18].
• Furthermore, the presence of reduced thiols (DTNB assay) and reduced glutathione (recycling assay) in CF sputum samples was evaluated [19].

Associations of DTNB with chemical compounds

• However, treatment of the inactive rhGIF with ethylmercurithiosalicylate or 5,5'-dithiobis(2-nitrobenzoic acid) (DTNB) resulted in the generation of derivatives whose bioactivity was comparable to that of the Ts-derived bioactive GIF [7].
• This shift in apoA-I mass to alpha electrophoretic mobility was blocked by the addition of either 1.4 mM DTNB or 10 mM menthol to the plasma prior to incubation, suggesting that lecithin:cholesterol acyltransferase (LCAT) activity was involved [20].
• Interestingly, the T5A mutant exhibited distinct metal thiolate activity in the EDTA and DTNB reactions, and also lost its bioactivity [21].
• It was shown previously that Cys-67 of the native enzyme reacted with 5,5'-dithiobis-(2-nitrobenzoic acid) (DTNB, Ellman's reagent) at pH 6.2, causing a reversible inactivation of the protease [22].
• The reactivity of this synthetic peptide with DTNB mimicked that of the protease, being more reactive in the absence of 6 M guanidine hydrochloride than in its presence [22].

Physical interactions of DTNB

• A beta-dystrobrevin antibody recognized a protein of the predicted size (71 kDa) that copurified with the dystrophin short form, Dp71 [13].
• Moreover, we found that Dp71, beta-dystroglycan and beta-dystrobrevin co-immunoprecipitated with the nuclear matrix proteins lamin B1 and actin [23].

Regulatory relationships of DTNB

• The use of DTNB in the initial staining step inhibits enzymes other than glutathione reductase that could be stained with the dichlorophenolindophenol/nitroblue tetrazolium counterstain [24].

Other interactions of DTNB

• Thus, like alpha-dystrobrevin, beta-dystrobrevin is likely to associate directly with dystrophin. alpha- and beta-dystrobrevins failed to copurify with each other, however [13].
• Both the membrane-permeable thiol-group oxidizing agent DTNP [2,2'-dithiobis-(5-nitropyridine)] and the membrane-impermeable DTNB [5,5'-Dithiobis-(2-nitrobenzoic acid)] (50 microM) inhibited Kv1.3 channels, suggesting that extracellular domains of Kv1.3 are affected [25].
• The analogues were competitive inhibitors with DTNB for reduction by thioredoxin reductase, with Ki values for III-2, IV-2, and VII-2 being 3.3, 13.0, and 8.6 microM, respectively [26].
• Labeling of free SH groups with tritiated NEM after preincubation of cells with DTNB and VIP made possible the characterization of reacting SH groups which probably belong to the receptor [27].
• Both this active mutant and wild-type NFI-C protein were inactivated by modification of their sulfhydryl residues with 5,5'-dithiobis(2-nitrobenzoic acid) (DTNB), and preincubation with an oligonucleotide containing an NFI-binding site gave partial protection against inactivation [28].

Analytical, diagnostic and therapeutic context of DTNB

• We constructed a series of human GIF mutants at site 5, and characterized their biochemical properties by UV spectroscopy, circular dichroism spectroscopy, EDTA reaction, 5,5'-dithiobis(2-nitrobenzoic acid) (DTNB) reaction, and pH titration [21].
• A series of MT3 variants around the EAAEAE hexapeptide have been prepared by site-directed mutagenesis and their properties and reactivity towards pH, EDTA and DTNB have been studied [29].
• DTNB, glutathione disulfide, and cystine were only marginally reduced by the cell cultures [30].
• The statistical average of glutathione values were measured by the DTNB method as 0.915 +/- 0.073 mg/g wet weight in test group and 0.126 +/- 0.008 mg/g wet weight in control group [31].
• Needle biopsies were obtained from the lateral gastrocnemius or vastus lateralis muscles and assayed for free and total carnitine concentrations via a 5,5'-Dithiobis-(2-nitrobenzoic acid) DTNB-linked spectrophotometric procedure [32].

References