4556-23-4Relevant articles and documents
Formation and reactions of S-nitroso proteins
Noble, Darren R.,Williams, D. Lyn H.
, p. 13 - 17 (2001)
Nitrosation of Bovine Serum Albumin (BSA) by nitrous acid occurs in two stages: a rapid step, which is consistent with an S-nitrosation reaction of a free cysteine unit, followed by a slower reaction which is consistent with an N-nitrosation reaction of a tryptophan residue. The fast reaction is catalysed by chloride and bromide ions (as is the reaction of free cysteine), whereas the slower reaction is not halide ion catalysed (like the reaction of tryptophan). Kinetic results were obtained for both reactions. The derived rate constants for the first stage for the reaction of ClNO and BrNO are reasonably close to the reported values for the reactions of cysteine. The second stage is a reversible process and we can estimate from measured infinity values and also from the variation in the measured rate constant for reactions at different [HNO2], values for the equilibrium constant of 3500 +/- 200 and 2600 +/- 200 dm3 mol-1 which compare reasonably with the reported value for the reaction of tryptophan of 850 dm3 mol-1. The pKa values of the cysteine residue in both BSA and Human Serum Albumin (HSA) were determined from rate measurements of the reactions with dipyridin-4-yl disulfide (4-aldrithiol), and yielded values of 8.32 and 8.18 respectively, which are close to the accepted value of 8.4 for cysteine itself, and which are substantially higher than the much quoted literature values. The S-nitroso derivatives of both BSA and HSA generated in solution (at ca. 1 x 10-4 mol dm-3) showed very little sign of decomposition at pH 7.4 when measured spectrophotometrically, even in the presence of added Cu2+. There was, however, clear evidence of rapid decomposition at much lower reactant concentration (ca. 1 x 10-6 mol dm-3) yielding nitric oxide in increasing amounts and rates, as Cu2+ is added. These results are discussed in terms of the complexation of the Cu2+ catalyst at different albumin derivative concentrations. Transnitrosation between the S-nitroso derivatives of both BSA and HSA and excess cysteine occurred very readily. These experiments were carried out in the presence of added Cu2+, and the decomposition of the resulting S-nitrosocysteine (S-NOCys) was monitored. The results support the suggestion that S-nitroso proteins can, in theory, act as a reservoir for NO which can readily be made available, either by the Cu2+-catalysed reaction, or more readily by a direct NO+ transfer to a low molecular weight thiol, such as cysteine, which is much more prone to yield NO rapidly and quantitatively by the Cu2+-catalysed pathway. The S-nitroso derivative of BSA also underwent a relatively slow decomposition reaction initiated by cysteine, even in the presenc...
Ago-allosteric modulators of human glucagon-like peptide 2 receptor
Yamazaki, Kazuto,Terauchi, Hiroki,Iida, Daisuke,Fukumoto, Hironori,Suzuki, Shuichi,Kagaya, Takaki,Aoki, Mika,Koyama, Koichiro,Seiki, Takashi,Takase, Kazuma,Watanabe, Misako,Arai, Tohru,Tsukahara, Kappei,Nagakawa, Junichi
, p. 6126 - 6135 (2012/10/30)
Glucagon-like peptide 2 (GLP-2) is an intestinotropic peptide that binds to GLP-2 receptor (GLP-2R), a class-B G protein-coupled receptor (GPCR). Few synthetic agonists have been reported so far for class-B GPCRs. Here, we report the first scaffold compounds of ago-allosteric modulators for human GLP-2R, derived from methyl 2-{[(2Z)-2-(2,5-dichlorothiophen-3-yl)-2-(hydroxyimino) ethyl]sulfanyl}benzoate (compound 1).
NOVEL AROMATIC COMPOUND AND POLYARYLENE COPOLYMER HAVING NITROGEN-CONTAINING HETEROCYCLE INCLUDING SULFONIC ACID GROUP IN SIDE CHAIN
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, (2010/06/22)
Provided is a solid polymer electrolyte having increased heat resistance and high proton conductivity and a proton conductive membrane composed of the electrolyte. Also provided is a copolymer having a sulfonic acid group. The copolymer includes a repeating unit represented by Formula (1): (in the formula, Y denotes at least one kind of structure selected from the group consisting of —CO—, —SO2—, —SO—, —CONH—, —COO—, —(CF2)l— (l is an integer of 1 to 10), and —C(CF3)2—; W denotes at least one kind of structure selected from the group consisting of a direct bond, —CO—, —SO2—, —SO—, —CONH—, —COO—, —(CF2)l— (l is an integer of 1 to 10), —C(CF3)2—, —O—, and —S—; Z denotes a direct bond or at least one kind of structure selected from the group consisting of —(CH2)l—(l is an integer of 1 to 10), —C(CH3)2—, —O—, —S—, —CO—, and —SO2—; R30 denotes a nitrogen-containing aromatic ring having a substituent represented by —SO3H, —O(CH2)hSO3H, or —O(CF2)hSO3H (h is an integer of 1 to 12); p is an integer of 0 to 10; q is an integer of 0 to 10; r is an integer of 1 to 5; and k is an integer of 0 to 4).
