Preparation cystamine

To the methods reviewed in an earlier volume 1 may be added the preparation by the oxidation of cystamine 2 and by the decarboxylation of cysteic acid.3 The method given in the procedure has appeared recently in the literature.4... 

Rhena-/3-ketoimine derivatives of several selected 2-ethylamino compounds have been prepared (36). These amines include 2-chloroethyl-amine (a DNA-alkylating reagent), cystamine ( a heparin antagonist), histamine (a potent vasodilator), tryptamine and O-methylserotonin (two indole alkaloids), and 0,0-dimethyldopamine (an adrenergic drug derivative). 

Using this approach, EGF has been successfully conjugated by disulfide exchange to the A chain of diphtheria toxin (Shimisu et al., 1980). A cystaminyl derivative of insulin also could be conjugated to the A chain of diphtheria toxin by this method (Miskimins and Shimizu, 1979). Other references to disulfide exchange using cystamine include Oeltmann and Forbes (1981) and Bacha et al. (1983) who prepared antibody-toxin and peptide-toxin conjugates, respectively. 

Add EDC (Thermo Fisher) to the solution prepared in (2) to obtain at least a 5-fold molar excess over the amount of cystamine present. React for 2 hours at room temperature. 

The complex bis(2-mercaptoethylamine)ethylenediaminechromium(III) perchlorate has beei prepared by the reaction of cystamine with aqueous solutions of chromium(II) in the presenct... 

Compound 98 was condensed with o-aminothiophenol, 2-aminoethanol, or cystamine in refluxing diphenyl ether through an intermolecular cyclization with the elimination of two molecules of water to give the polyfused derivatives 101-103, respectively. Also, the reactions of 98 with dimethylthiomethylenemalononitrile in boiling dimethylforma-mide (DMF) were studied. The dimethylthiomethylenemalononitrile was prepared via the reaction of malononitrile with CS2 with 2 equiv of methyl iodide in a one-pot reaction using liquid-liquid phase-transfer catalysis (PTC) technique (NaOH/dioxane/tetrabutylammonium bromide (TBAB)). The product of this reaction was identified as 8-cyano-9-imino-7-methylthio-6-oxo-3-phenyl-5,6,8,9-tetrahydro-77/-pyrano[3,2-/][l,2,4]-triazolo[3,4-A][l,3,4]thia-diazepine 104 (Scheme 10). 

Acetylcholineesterase and choline oxidase Au foil was treated with cystamine to produce a base layer of ami-nothiolate units, was derivatized by reaction of the amino group and disodium-4,4 -diisothiocyanato-trans-stilbene-2,2 -disulfonate. Enzymes were immobilized at the isothiocyanate group via thiourea link. The bifunctional sensor for ACh was prepared by stepwise immobilization of four layers of the enzyme ChO and three layers of AChE. Choline generated was detected amperometircally with the use of 2,6-dichloro-phenolindophenol as a mediator in solution. Electrical communication between the enzyme and the electrode is achieved either by the use of ferrocenecar-boxylic acid as mediator in the assay buffer or by immobilization of [(ferrocenyl methyl)amino] hexa-noic acid on the enzyme layer. [92]... 

Figure 17. (A) The preparation of an electrically wired enzyme by the reconstitution technique, involving the removal of the native FAD cofactor from the enzyme (e.g., GOx) and the incorporation of the artificial FAD-ferrocene dyad into the apo-enzyme. (B) Cyclic voltammograms of a system consisting of ferrocene-FAD-reconstituted GOx (1.75 mg mL ) at various concentrations of glucose (a) 0, (b) 1, (c) 3 and (d) 20.5 mM. Experiments were performed in 0.1 M phosphate buffer, pH 7.3, at 35 C, using a cystamine-modified Au electrode, potential scan rate 2 mV s , under argon. Inset calibration curve of the biocatalytic current (0.5 V vs. SCE) at different glucose concentrations.

Scheme 3. Idealized sketch of a gold surface modified with a multilayered assembly prepared by (a) alternate deposition of layers of poly(acryhc acid) and poly-L-lysine on a positively charged cystamine SAM (the multilayer assembly is stabilized by electrostatic interactions between adjacent layers, [136]) and by (b) covalent attachment of a layer of G4 poly(amidoamine) dendrimer to a 11-mercapto-l-undecanoic acid SAM after activation of the surface-bound cEirboxylic groups with pentafiuorophenol and EDC. The dendrimer monolayer is afterwards biotinylated by covalent binding of desthiobiotin amidocaproate (not shown) to assemble an overlayer of avidin by affinity interactions [133].

Scheme 10. Idealized sketch of modified gold surfaces prepared by solid-phase covalent binding of a ligand (a triazine dye) to a (a) 3-mercaptopropionic acid SAM (b) 3-mercaptopropanol SAM (c) 3-mercaptopropionic acid SAM derivatized with 1,4-diaminobutane (d) cystamine SAM derivatized with fumaric acid (e) mixed 3-mercaptopropanol and 3-mercaptopropionic acid SAM derivatized with 1,4-diaminobutane and (f) mixed propanethiol and 3-mercaptopropionic acid SAM derivatized with 1,4-diaminobutane (approaches (a) and (b) were used to attach triazine dyes to 11-mercapto-l-undecanoic acid and 11-mercapto-l-undecanol SAMs). Reproduced from [240] with permission.

Scheme 11. Idealized sketch showing the electroen matic oxidation of L-lactate at gold modified electrode surfaces, (a) Lactate dehydrogenase bound to CB-terminated alkylthiol SAMs prepared by covalent attachment of CB to 3-mercaptopropionic acid SAM derivatized with 1,4-diaminobutane. The electroenzymatic oxidation of lactate is observed only in the presence of soluble coenzyme (NAD" ") and a redox mediator (phenazine methosulfate) [215]. (b) Lactate deh3tdrogenase bound to NAD-terminated alkylthiol SAMs prepared by covalent attachment of Af -(2-aminoethyl)-NAD to a cystamine SAM derivatized with pjrrroloquinoline quinone. The reconstituted enzyme is electrically wired to the electrode surface via two NAD" -binding pockets involved in the affinity-binding surface reaction [242].

Integrated electrically-contacted enzyme electrodes were prepared by the surface reconstitution of different apo-enzymes on electrode surfaces. The pyrroloquinoline quinone, PQQ, (7), was covalently linked to a cystamine monolayer associated with an Au-electrode, and A -(2-aminoethyl-FAD), (8), was covalently attached to the PQQ units. Fig. 3-4A. The integrated enzyme-electrode was then prepared by the reconstitution of apo-GOx on the FAD units. The surface coverage of the PQQ-FAD units was estimated to be 5.5x10 ° mole cnr. whereas the surface coverage of the reconstituted... 

A putative y-amide derivative was also prepared from MTX by reaction with cystamine in water solution in the presence of EDC hydrochloride, followed by reduction of the disulphide bond with excess 2-mercaptoethanol [328]. The resulting thiol (VIII.220) was then allowed to react with... 

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