Effect of disulfide bonds

Allen S, Naim HY, Bulleid NJ (1995), Intracellular folding of tissue-type plasminogen activator. Effects of disulfide bond formation on N-linked glycosylation and secretion, J. Biol. Chem. 270 4797-4804. 

Figure 17. The effect of disulfide bond modification of turkey ovomucoid by alkali on inhibitory activity against trypsin (T), a-chymotrypsin, (C), and subtilisin (S). Turkey ovomucoid (O.lOmM) was treated with alkali (lOOmM NaOH) at 23°C. Sulfhydryl content (moles per mole of protein)...

Elhott S, Chang D, Delorme E, Dunn C, Egrie J, Giffin J, Lorenzini T, Talbot C, Hesterberg L. Isolation and characterization of conformation sensitive antieryth-ropoietin monoclonal antibodies effect of disulfide bonds and carbohydrate on recombinant human erythropoietin structure. Blood 1996 87 2714-22. 

Nielsen HC, Beckwith AC, Wall JS. Effect of disulfide-bond cleavage on wheat gliadin fractions obtained by gel filtration. Cereal Chem 1968 45 37-47. 

Friedman, M., Grosjean, O.K. and Zahnley, J.C. (1982c). Effect of disulfide bond modification on the structure and activities of enzyme inhibitors. "Mechanisms of Food Protein Deterioration", J.P. Cherry, Ed., ACS Symp. Series,... 

V Kasche, R Schlothauer, G Brunner. Enzyme denaturation in supercritical carbon dioxide stabilizing effect of disulfide bonds during the depressurization step. Biotechnol Lett 10 569-574, 1988. 

Disulfides. The introduction of disulfide bonds can have various effects on protein stability. In T4 lyso2yme, for example, the incorporation of some disulfides increases thermal stability others reduce stability (47—49). Stabili2ation is thought to result from reduction of the conformational entropy of the unfolded state, whereas in most cases the cause of destabili2ation is the introduction of dihedral angle stress. In natural proteins, placement of a disulfide bond at most positions within the polypeptide chain would result in unacceptable constraint of the a-carbon chain. 

They also found that at 1O8 C protein aggregation occurred, probably as a result of disulfide bond formation, and they suggested that this effect might provide an alternative to chemical oxidation for dough improvement. At higher temperatures, the protein aggregates broke down. The authors postulated that at the higher temperatures not only... 

Livney, Y.D., Verespej, E., and Dalgleish, D.G. 2003. Steric effects governing disulfide bond interchange during thermal aggregation in solutions of beta-lactoglobulin B and alpha-lactalbumin. J Agric Food Chem. 51(27) 8098-8106. 

Mercaptoethanol (0.42 M) destroyed the chromogenic capacity of metal-free ovotransferrin with little or no effect on the iron complex. 2-Mercaptoethanol was effective on the metal-free ovotransferrin at a lower concentration in the presence of urea. Similar effects were obtained with sulfite and urea, and the inactivations obtained were directly proportional to the number of disulfide bonds cleaved (Table 12). When slightly under half of the disulfide bonds were cleaved (4.8 or 11 total), essentially complete and irreversible inactivation of metal-free ovotransferrin... 

Many, but not all, proteins are sensitive to alterations in the oxidation-reduction potential of their environment. The effect is caused in part by oxidation of sulfhydryl groups or reduction of disulfide bonds. Not all proteins are equally sensitive to such alterations, but when they are, it is critical to be aware of their sensitivity. The purification or assay of some proteins can be accomplished only by providing reducing conditions (reduced glutathione, free cysteine, dithiothreitol, or mercap-toethanol) in all buffer solutions. 

In previous papers, we have (a) reviewed elimination reactions of disulfide bonds in amino acids, peptides, and proteins under the influence of alkali (5) (b) analyzed factors that may operate during alkali-induced amino acid crosslinking and its prevention (6) (c) demonstrated inhibitory effects of certain amino acids and inorganic anions on lysinoalanine formation during alkali treatment of casein, soy protein, wheat gluten, and wool and on lanthionine formation in wool ( 7, 9) (d) demonstrated that... 

The conversion of disulfide bonds to thiol groups has a much greater effect on the physical properties of wool than conversion to (S-methyl groups (Crewther, 1965b). Reduction of relatively few disulfides and the consequent small increase in thiol content give maximum extensions > 100 % and high strains at the end of the yield region. 

The magnitude of the changes in longitudinal and torsional stiffness of wool caused by rupturing disulfide bonds is very dependent on the relative humidity used for stressing the fibers. In dry fibers the effects of disulfide rupture are small or not apparent (Harris and Brown, 1946 Feughelman, 1963 Feughelman and Mitchell, 1964). 

The predominant contribution of the folded native structure is amply illustrated by the findings that complete reduction of disulfide bonds and 5-carboxymethylation completely alters the immunochemical reactivity of protein antigens, such as ribonuclease, lysozyme, and other antigens.However, reduction of but two of the four disulfide bonds in ribonuclease had a negligible effect on the ability to precipitate with antibody to native ribonuclease. 

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