Cysteamine disulfide

A yield of 89% for D-penicillamine from its homodisulfide using a 10-fold excess of DTT at 60 °C (4 h) has been claimed. Comparative studies with cysteine-D-penicillamine disulfide or protein-bound D-penicillamine were not reported. Kelly et al. reduced cysteamine disulfides and protein-cysteamine with DTT prior to HPLC-ED. However, excess DTT can produce analytical problems since both DTT and its oxidised form are readily separated by RPLC and can be detected electrochemically. 

Potassium hydroxide Cysteamine Carbon disulfide Dimethyl sulfate Sodium Ammonia Cyanamide Methylamine ... 

Fig. 9.1 Tethering schematic. A fragment will be selected if it has inherent affinity for the protein and binds in the vicinity of the cysteine residue. An example disulfide-containing fragment is shown below, illustrating the variable portion, the linker, and the cysteamine piece that is lost when the fragment forms a disulfide bond with the protein.

Cysteamine (/3-mercapto-ethylamine) is used for the treatment of nephropathic cystinosis. Cysteamine converts within lysosomes cystine into cysteine and cysteine-cysteamine mixed disulfide, both of which can exit the lysosome thus removing the extra cystine. After oral administration peak plasma levels are reached at about 1.4 hours post dose. It is eliminated as a sulfate in the urine with a half-life of 4-5 hours. The most frequent adverse reactions seen involve the gastrointestinal and central nervous systems. Side effects include abdominal pain, diarrhea, drowsiness, fever, loss of appetite, nausea or vomiting and skin rash. Confusion, dizziness and headache may occur. 

Characterization of the activities of the horse and pig enzymes has shown that pantetheinase is specific for the pantothenate moiety of its substrate and will not react with CoA, 4 -phosphopantetheine, or /i-alanylcys-teamine. However, it accepts the modification of the cysteamine moiety and hydrolyzes a variety of pantetheine thioesters. The enzyme does not require any cofactors, although it is inhibited by pantetheine (pantetheine disulfide), oxidized glutathione, and thiol inhibitors (such as Hg ), suggesting the involvement of an active site cysteine in catalysis. The pig enzyme has a molecular weight of 72 kDa and exhibits a A n, of 20pmoll for pantetheine. All these studies have been performed on purified or partially purified native enzymes no pantetheinase enzyme has been cloned to date. 

The results of chromate reduction by the model compounds listed in Table 2, allow us to predict the environment that the SH groups in a protein will require for them to react readily with chromate. The fastest reductants (Table 2) are either neutral (e.g., cysteine, penicillamine) or have a positive charge (cysteamine). However, charge is not the only factor affecting the kinetics, since the cysteine-chromate reaction is faster than the cys-teamine-chromate reaction and the unithiol-chromate reaction is faster than the DTT-chromate reaction. The obvious advantage that cysteine has over cysteamine is its ability to chelate intermediate Gr species after the disulfide bond has been formed, as illustrated in Fig. 3. Such chelation would facilitate the change in coordination number required in going from Cr(VI) to Cr(IV) or Cr(III) (see Sect. 2). 

Numerous reducing agents have been applied for the cleavage of disulfides in peptides. Reduction with sodium in liquid ammonia, with cysteine, 2-mer-captoethanol, 2-mercaptoacetic acid, 2-mercaptoethylamine (cysteamine), borohydrides and trialkylphosphines were used both for preparative and for... 

CS-based pH-sensitive nanogds with an average size of 170nm were prepared by utilizing the formation of polydectrolyte complexes." In this procedrue, CS formed polydectrolyte complexes with cysteamine-functionalized polyaspartic add and resulting polymer aggregates were aoss-linked by chloramine-T-mediated disulfide formation. 

Nanogels based on disulfide-cross-linked heparin were prepared to promote efficient cellular uptake of heparin in order to induce apoptotic cell death. Thiol-functionalized heparin was synthesized by selective oxidation of n-glucuronic acid residues in heparin stmaure with sodium periodate followed by the addition of cysteamine hydrochloride. 

X.Liu addressed this question using biologically relevant molecules and model compounds that can interact with Au(0) surfaces cystamine, cysteamine, biotinylated thiol-6 and biotinylated disulfide-5, as well as the thiols 11-mercapto-l-undecanol and 11-mercapto undecanoic acid [26]. In each case, the molecule was added to a dry Si02-X-Au(III) aerogel before photolysis. 

Mice lacking pantetheinase exhibit weaker inflammatory responses compared with wild-type mice may be due to less ability to hydrolyse pantetheine followed by the production of cysteamine and pantothenic acid. Extensive investigations using vanin-1-deficient mice show that cysteamine is more responsible for inflammatory response than pantothenic acid. Administration of cysteamine or cystamine (an oxidized dimer of cysteamine) recovers inflammatory response in vanin-1-deficient mice as much as wild-type mice show (Berruyer et al. 2004, 2006 Martin et al. 2004 Meghari et al. 2007 Pouyet et al. 2010 Roisin-Boulfay et al. 2008), suggesting that cysteamine is a key molecule that induces inflammatory response. Since cysteamine has sulfhydryl group in its molecule, it has an ability to cleave the disulfide bonds of cystine (a dimeric amino acid formed covalently by the oxidation of two cysteine residues). 

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