disulfide bond

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bond

 [bond]
the linkage between atoms or radicals of a chemical compound, or the symbol representing this linkage and indicating the number and attachment of the valencies of an atom in constitutional formulas, represented by a pair of dots or a line between atoms, e.g., H—O—H, H—C≡C—H or H:O:H, H:C:::C:H.
coordinate covalent bond a covalent bond in which one of the bonded atoms furnishes both of the shared electrons.
covalent bond a chemical bond between two atoms or radicals formed by the sharing of a pair (single bond), two pairs (double bond), or three pairs of electrons (triple bond).
disulfide bond a strong covalent bond, —S—S—, important in linking polypeptide chains in proteins, the linkage arising as a result of the oxidation of the sulfhydryl (SH) groups of two molecules of cysteine.
high-energy phosphate bond an energy-rich phosphate linkage present in adenosine triphosphate (ATP), phosphocreatine, and certain other biological molecules. On hydrolysis at pH 7 it yields about 8000 calories per mole, in contrast to the 3000 calories yielded by phosphate esters. The bond stores energy that is used to drive biochemical processes, such as the synthesis of macromolecules, contraction of muscles, and the production of the electrical potentials for nerve conduction.
high-energy sulfur bond an energy-rich sulfur linkage, the most important of which occurs in the acetyl-CoA molecule, the main source of energy in fatty acid biosynthesis.
hydrogen bond a weak, primarily electrostatic, bond between a hydrogen atom bound to a highly electronegative element (such as oxygen or nitrogen) in a given molecule, or part of a molecule, and a second highly electronegative atom in another molecule or in a different part of the same molecule.
ionic bond a chemical bond in which electrons are transferred from one atom to another so that one bears a positive and the other a negative charge, the attraction between these opposite charges forming the bond.
peptide bond the —CO—NH— linkage formed between the carboxyl group of one amino acid and the amino group of another; it is an amide linkage joining amino acids to form peptides.

di·sul·fide bond

a single bond between two sulfurs; specifically, the -S-S- link binding two peptide chains (or different parts of one peptide chain); also occurs as part of the molecule of the amino acid, cystine, and is important as a structural determinant in many peptide and protein molecules, for example, keratin, insulin, and oxytocin. A symmetric disulfide is R-S-S-R; R'-S-S-R is a mixed or asymmetric disulfide.

di·sul·fide bond

(dī-sŭl'fīd bond)
A single bond between two sulfurs; specifically, the -S-S- link binding two peptide chains (or different parts of one peptide chain).
Synonym(s): disulphide bond.
References in periodicals archive ?
Tissue plasminogen activator (tPA) is a serine protease, which is composed of five distinct structural domains with 17 disulfide bonds, representing a model of high-disulfide proteins in human body.
Few researchers have investigated the first steps of HIV infection, says Ryser, especially since the disulfide bonds in HIV were thought to be inaccessible to enzymes.
The reduction of the disulfide bonds between aminothiols and plasma proteins and the reduction of aminothiol disulfides probably represent one of the most delicate steps in the determination of total plasma aminothiols.
When hair fibers show a decrease in stress-to-break after UVB exposure, they have lost tensile strength, primarily due to the breaking of disulfide bonds inside the cortex.
Disulfide bonds in the sample are reduced when the sample is combined with the first reagent.
In the reduction of disulfide bonds, dithiothreitol has been a widely used reagent (10, 11).
Because HCySH circulates mostly as disulfides complexed with albumin, measurement of plasma total HCySH involves reduction of these disulfide bonds and detection of the generated HCySH.
However, homocystine undergoes an exchange reaction with free sulfhydryls, including cysteine, readily forming covalent disulfide bonds with these thiols, and gradually disappears as a free amino acid (1).
In most species, LEAP-2 is a cysteine-rich and cationic protein [14,15], which generally has a conserved core structure with two disulfide bonds that play a crucial role in bacterial killing [16].
It breaks the disulfide bonds of your hair, around a selected cylindrical rod creating a curl pattern.
Plasma levels of TDB in the patient and control groups were simultaneously tested via a novel colorimetric method developed by Erel O et al.10 In this method, reducible disulfide bonds (SS) are first reduced to free thiol groups (SH) using NaBH.