disulfide bond

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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.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.

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.
Farlex Partner Medical Dictionary © Farlex 2012

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.
Medical Dictionary for the Health Professions and Nursing © Farlex 2012
References in periodicals archive ?
Novel synthetic analogues of avian [beta]-defensin-12: the role of charge, hydrophobicity, and disulfide bridges in biological functions.
The conserved cysteine residues are highlighted in yellow, which gives rise to predicted disulfide bridges (black lines), the dotted line represented one intra-chain disulfide bonds.
This is also consistent with the negligible attachment of DNA probes through formation of disulfide bridges, Figure 3.
For disulfide bridge identification, the sample was prepared with the same methods as described above without reduction and digested using both trypsin and Glu-C enzyme at a 1:1:40 ratio of trypsin :Glu-C: sample.
Thus, shifting cysteine residues towards each other until the distance between them reached SS bridge length (2.04 A) and subsequent formation of disulfide bridges make greater changes in the structure of the molecule than incorporation of glutathione.
Maurotoxin, a four disulfide bridge toxin from Scorpio maurus venom: Purification, structure and action on potassium channels.
Papain, cysteine protease hydrolase enzyme is very resistant and severe, which consists of number of amino acids in the range of 212-218 and shows a great degree of homologous.Structure of papain composed of a single polypeptide chain having 3 disulfide bridges and papain enzymatic activity can be determined through sulfhydryl group.
The mannoproteins of yeast can form disulfide bridges with sulfur compounds and lessen their aromatic impact.
The hepatic peptide hormone hepcidin is a highly conserved molecule of only 25 amino acids with 4 disulfide bridges that plays a central role in body iron metabolism (2).
Controlled release properties of polymers are reported to be increased by thiolation due to formation of disulfide bridges within the polymer [19].
Native, denaturing, and denaturing-reducing conditions allow for the quantification of the free cysteine's thiols coming from degradation, unfolding, or broken disulfide bridges buried in the protein and the total cysteines content within the protein, respectively.