Thiols, Disulphides and Thiosulphates: Some New Reactions and Possibilities in Peptide and Protein Chemistry

Swan, JM

doi:10.1038/180643a0

Cited by 222 publications

(66 citation statements)

References 13 publications

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“…The method of disulfide bond formation described here should be of general applicability for synthesis of either symmetrical or asymmetrical heterobifunctional reagents, varying in the length of the spacer. It can be argued that although disulfide-containing compounds are prone to sulfur exchange, they can be used with sulfhydryl or disulfide-containing proteins, under controlled conditions of pH ( 13,(34)(35)(36). Preliminary experiments suggest that reagent 4 is of general applicability for the study of peptide hormone-receptor (Dupuis and Lehoux, unpublished).…”

Section: Resultsmentioning

confidence: 99%

An asymmetrical disulfide-containing photoreactive heterobifunctional reagent designed to introduce radioactive labeling into biological receptors

Dupuis¹

1987

Can. J. Chem.

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GILLES DUPUIS. Can. J. Chem. 65, 2450Chem. 65, (1987. The synthesis of succinimido l-amino-(4-azidosalicyloyl)-3,4-dithio-5-carboxylate, a heterobifunctional photoaffinity labeling reagent, is described. The cross-linker possesses an asymmetrical disulfide bond, and a general method for generating a spacer arm bearing an asymmetrical or symmetrical disulfide bond is detailed. The heterobifunctional reagent has been obtained in a minimum of steps and intermediates have been characterized. It is further shown that the reagent can be trace-labeled with ['25~]-iodine and it has been used to modify phytohemagglutinin, a model protein. Upon irradiation, polymeric phytohemagglutinin derivatives are produced, as evidenced by electrophoretic analysis.GILLES DUPUIS. Can. J. Chem. 65, 2450Chem. 65, (1987. On dCcrit la synthtse du succinimido amino-4 (azido-4 salicyloyl) dithio-3,4 carboxylate-5, un rtactif de marquage photoaffinitaire hCtCrobifonctionne1. L'agent rtticulant posskde une liaison disulfure asymttrique et on dCcrit une mtthode g6nCrale permettant de gCnCrer un bras d'espacement portant une liaison disulfure asymttrique ou symttrique. On a obtenu le reactif hCt6robifonctionnel en faisant appel B un nombre minimal d'etapes et on a caracterist les intermkdiaires. On a de plus demontrt que le rtactif peut &tre marque B I'ttat de traces avec de l'iode I2'I et on I'a utilisC pour modifier la phytohemaglutinine, une proteine modtle. Par irradiation, il y a formation de polymkres dtrivCs de la phytohtmaglutinine qui ont t t t mis en evidence par analyse par Clectrophorese.[Traduit par la revue]

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Section: Resultsmentioning

confidence: 99%

An asymmetrical disulfide-containing photoreactive heterobifunctional reagent designed to introduce radioactive labeling into biological receptors

Dupuis¹

1987

Can. J. Chem.

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“…Table 4 lists the purification procedures developed to obtain keratin derivatives. For a-keratinous materials, reduction, oxidation and sulfitolysis methods have been used to generate satisfactory amounts of the derivatives [16,[64][65][66][67]; while for b-keratinous materials, which have not been as extensively investigated as a-keratin, alkaline thioglycollate and a combination of a disulfide bond-breaking reagent and a protein denaturant were described in literature [68,69]. There are also reports discussing degraded keratins produced by partial hydrolysis (with acid, alkali or enzymes) of wool, hair and feathers.…”

Section: Solubility and Amino Acid Compositionsmentioning

confidence: 99%

“…Reduction: by potassium thioglycollate in urea to obtain 80-97% keratin from horn, hoof, hair, and further by starch-gel electrophoresis into high-sulfur and lowsulfur fractions [16,64,65] Alkaline thioglycollate [68]: by sodium thioglycollate in the absence of oxygen at PH 11 to obtain 80-90% feather keratin [69] Oxidation: By treating wool with peracetic acid and dilute alkali [66] Combination of a disulfide bond-breaking reagent and a protein denaturant Sulfitolysis: By sodium bisulfite with urea and an oxidizing agent [67] in feather rachis may be correlated with the lack of helical secondary structure. Both exhibit very low content of histidine and methionine.…”

Section: A-keratin B-keratinmentioning

confidence: 99%

Keratin: Structure, mechanical properties, occurrence in biological organisms, and efforts at bioinspiration

Wang

Yang

McKittrick

et al. 2016

Progress in Materials Science

658

474

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a b s t r a c tA ubiquitous biological material, keratin represents a group of insoluble, usually high-sulfur content and filament-forming proteins, constituting the bulk of epidermal appendages such as hair, nails, claws, turtle scutes, horns, whale baleen, beaks, and feathers. These keratinous materials are formed by cells filled with keratin and are considered 'dead tissues'. Nevertheless, they are among the toughest biological materials, serving as a wide variety of interesting functions, e.g. scales to armor body, horns to combat aggressors, hagfish slime as defense against predators, nails and claws to increase prehension, hair and fur to protect against the environment. The vivid inspiring examples can offer useful solutions to design new structural and functional materials.Keratins can be classified as a-and b-types. Both show a characteristic filament-matrix structure: 7 nm diameter intermediate filaments for a-keratin, and 3 nm diameter filaments for b-keratin.Both are embedded in an amorphous keratin matrix. The molecular unit of intermediate filaments is a coiled-coil heterodimer and that of b-keratin filament is a pleated sheet. The mechanical response of a-keratin has been extensively studied and shows linear Hookean, yield and post-yield regions, and in some cases, a high reversible elastic deformation. Thus, they can be also be considered 'biopolymers'. On the other hand, b-keratin has not been investigated as comprehensively. Keratinous materials are strain-rate sensitive, and the effect of hydration is significant.Keratinous materials exhibit a complex hierarchical structure: polypeptide chains and filament-matrix structures at the nanoscale, Progress in Materials Science 76 (2016) 229-318 Contents lists available at ScienceDirect Progress in Materials Sciencej o u r n a l h o m e p a g e : w w w . e l s e v i e r . c o m / l o c a t e / p m a t s c i organization of keratinized cells into lamellar, tubular-intertubular, fiber or layered structures at the microscale, and solid, compact sheaths over porous core, sandwich or threads at the macroscale. These produce a wide range of mechanical properties: the Young's modulus ranges from 10 MPa in stratum corneum to about 2.5 GPa in feathers, and the tensile strength varies from 2 MPa in stratum corneum to 530 MPa in dry hagfish slime threads. Therefore, they are able to serve various functions including diffusion barrier, buffering external attack, energy-absorption, impact-resistance, piercing opponents, withstanding repeated stress and aerodynamic forces, and resisting buckling and penetration.A fascinating part of the new frontier of materials study is the development of bioinspired materials and designs. A comprehensive understanding of the biochemistry, structure and mechanical properties of keratins and keratinous materials is of great importance for keratin-based bioinspired materials and designs. Current bioinspired efforts including the manufacturing of quill-inspired aluminum composites, animal horn-inspired SiC composites, and feather-i...

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“…16 In the absence of Cu + + or NH40H 5% conversion was observed. In the absence of SOs: no conversion occurred.…”

mentioning

confidence: 96%

The Twisted Circular Form of Polyoma Viral DNA

Vinograd¹,

Lebowitz²,

Radloff³

et al. 1976

The Biology of DNA Tumor Viruses

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The major part of the DNA from polyoma virus has been shown to consist of circular base-paired duplex molecules without chain ends.' -' The intertwined circular form accounts for the ease of renaturation4 of this DNA and the failure of the strands to separate in strand-separating solvents. I-' In previous studiesl-3 a minor component, II, observed in variable amounts in sedimentation analyses of preparations of polyoma DNA at neutral pH, was regarded to be a linear form of the viral DNA. Both the major component I (20S) and II (16S) were infective." I In our further investigations of the minor component the following results, which are reported below, have been obtained: (1) The minor component is a ring-shaped duplex molecule. (2) It is generated by introducing one single-chain scission in component I by the action of pancreatic DNAase or chemical-reducing agents. (3) The sedimentation coefficient of II is insensitive to several single-strand scissions. (4) The conversion products, when not excessively attacked, are infective.The foregoing results raised a new problem. Why does the viral DNA, an intact duplex ring, sediment 20 per cent faster than a similar duplex ring containing one or more single-strand scissions? Experiments bearing on this problem, presented below, indicate the presence of a twisted circular structure in polyoma DNA I. A mechanism for the formation of this locked-in twisted structure is proposed.Methods.-Isolation and purification of the virus and extraction of the DNA: Two methods6 7 for purification of the virus were used. The DNA was isolated by Weil's method4 except that the phenol was freshly distilled under argon.Ultracentrifugation: Sedimentation analyses were performed in a Spinco model E ultracentrifuge by band centrifugation.8 Some of the results were recorded with the photoelectric scanning attachment.9, " Sucrose density gradient experiments were performed at 40, 30,000 rpm, and 9 hr. The 3% and 20% sucrose solutions contained SSC (0.15 M NaCl and 0.015 M Na citrate) and 0.05 M Tris chloride pH 8.0.Enzymes: Pancreatic DNAase, 1 X crystallized, was obtained from Worthington Biochemicals

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Thiols, Disulphides and Thiosulphates: Some New Reactions and Possibilities in Peptide and Protein Chemistry

Cited by 222 publications

References 13 publications

An asymmetrical disulfide-containing photoreactive heterobifunctional reagent designed to introduce radioactive labeling into biological receptors

An asymmetrical disulfide-containing photoreactive heterobifunctional reagent designed to introduce radioactive labeling into biological receptors

Keratin: Structure, mechanical properties, occurrence in biological organisms, and efforts at bioinspiration

The Twisted Circular Form of Polyoma Viral DNA

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