Examples of disulfide bond in the following topics:
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- ., formation of disulfide bridges).
- For instance, the peptide hormone insulin is cut twice after disulfide bonds are formed, and a propeptide is removed from the middle of the chain; the resulting protein consists of two polypeptide chains connected by disulfide bonds.
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- Another option is the use of chemical depilatories, which work by breaking the disulfide bonds that link the protein chains that give hair its strength.
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- The antigen receptor of MHC-restricted CD4 helper T cells and CD8 cytolytic T cell is a heterodimer consisting of two transmembrane polypeptide chains, designated alpha and beta, covalently linked to each other by disulfide bonds.
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- Cysteine is a thiol, and like most thiols it is oxidatively dimerized to a disulfide, which is sometimes listed as a distinct amino acid under the name cystine.
- Disulfide bonds of this kind are found in many peptides and proteins.
- For example, the two peptide chains that constitute insulin are held together by two disulfide links.
- In the manipulation called "permanent waving", disulfide bonds are first broken and then created after the hair has been reshaped.
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- The secondary structures of these molecules follow four themes, including i) α-helical, ii) β-stranded due to the presence of two or more disulfide bonds, iii) β-hairpin or loop due to the presence of a single disulfide bond and/or cyclization of the peptide chain, and iv) extended.
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- Cysteine side chains form disulfide linkages in the presence of oxygen, the only covalent bond forming during protein folding.
- Enzymes often play key roles in bonding subunits to form the final, functioning protein.
- For example, insulin is a ball-shaped, globular protein that contains both hydrogen bonds and disulfide bonds that hold its two polypeptide chains together.
- Silk is a fibrous protein that results from hydrogen bonding between different β-pleated chains.
- The tertiary structure of proteins is determined by hydrophobic interactions, ionic bonding, hydrogen bonding, and disulfide linkages.
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- The formulas written here neutralize this charge separation by double bonding that expands the valence octet of sulfur.
- Indeed, the S=O double bonds do not consist of the customary σ & π-orbitals found in carbon double bonds.
- As a third row element, sulfur has five empty 3d-orbitals that may be used for p-d bonding in a fashion similar to p-p (π) bonding.
- The S–S single bond is nearly twice as strong as the O–O bond in peroxides, and the O–H bond is more than 25 kcal/mole stronger than an S–H bond.
- Thus, thermodynamics favors disulfide formation over peroxide.
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- Compounds with carbon–sulfur bonds are uncommon except for carbon disulfide, a volatile colorless liquid that is structurally similar to carbon dioxide.
- Sulfur-sulfur bonds are a structural component to stiffen rubber, similar to the biological role of disulfide bridges in rigidifying proteins.
- In the most common type of industrial "curing" or hardening and strengthening of natural rubber, elemental sulfur is heated with the rubber until chemical reactions form disulfide bridges between isoprene units of the polymer.
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- Another form, scarlet phosphorus, is obtained by allowing a solution of white phosphorus in carbon disulfide to evaporate in sunlight.
- It consists of tetrahedral P4 molecules, in which each atom is bound to the other three atoms by a single bond.
- White phosphorus is insoluble in water but soluble in carbon disulfide.
- It can be viewed as a derivative of P4 -- one of the P-P bonds is broken, and one additional bond is formed between the neighboring tetrahedrons, resulting in a chain-like structure.
- The most important elemental form of phosphorus is white phosphorus, P4, which exhibits the bonding shown.
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- Molecular compounds are made when two or more elements share electrons in a covalent bond to connect the elements.
- Typically, non-metals tend to share electrons, make covalent bonds, and thus, form molecular compounds.