Dynamic Detection of Thiol Oxidation/Reduction Status During the Conversion of Cysteine/Cystine

2021 ◽  
pp. 131675
Author(s):  
Xun Zhang ◽  
Bin Yang ◽  
Wenlong Zhou ◽  
Zhenqi Zhu ◽  
Yujing Bian ◽  
...  
Keyword(s):  
Thiol Oxidation ◽  
Oxidation Reduction ◽  
Dynamic Detection

scholarly journals Phagocytosis-induced chemotaxis receptor cycling in neutrophils is mediated by thiol oxidation

Blood ◽  
1982 ◽  
Vol 59 (6) ◽  
pp. 1337-1343
Author(s):  
TA Lane ◽  
GE Lamkin
Keyword(s):  
Important Determinant ◽  
Receptor Occupancy ◽  
Thiol Groups ◽  
Thiol Oxidation ◽  
Chemotactic Peptide ◽  
Oxidation Reduction ◽  
Dependent Inhibition ◽  
Dose Dependent ◽  
Physiologic Role ◽  
Mediated Reduction

We previously demonstrated that neutrophil (PMN) phagocytosis of opsonized zymosan (OPZ) caused oxygen-dependent inhibition of chemotactic peptide receptor (CPR) binding using the ligand 3H-formyl- methionyl-leucyl-phenylalanine (3H-FMLP). In the current studies we sought to determine the mechanism of CPR inhibition by OPZ. We found that 3 mM cysteine and 5 mM dithiothreitol (DTT) did not decrease PMN phagocytosis, but abolished CPR inhibition by OPZ. Furthermore, incubation of PMN with DTT after OPZ partially restored the suppressed CPR. PMN CPR saturation studies with 3H-FMLP on PMN incubated with or without DTT after phagocytosis indicated that DTT restored receptor numbers to 92% +/- 6% of prephagocytosis values and also improved CPR affinity for 3H-FMLP. In additional studies we found that the cell penetrating thiol reagents mercuric chloride (HgCl2), N-ethylmaleimide (NEM), and diamide, but not the nonpenetrating agents p- chloromercuriphenylsulfonic acid and p-chloromercuribenzoate, caused rapid, dose-dependent, DTT-inhibitable suppression of up to 85% CPR binding. CPR inhibition by HgCl2 and NEM was irreversible. PMN CPR saturation studies showed that NEM decreased total receptor numbers, not CPR affinity. The effect of NEM was not inhibited by receptor occupancy at 4 degree C or at 37 degree C. These studies indicate that: (1) intact thiol groups are a requirement for CPR ligand-binding; (2) the thiol groups are presumptively located on the interior side of, or within hydrophobic portions of, the plasma membrane and are not part of the 3H-FMLP binding site; (3) thiol oxidation-reduction induces reversible alteration in CPR binding; (4) phagocytosis-induced modulation of the CPR is due, in part, to thiol oxidation. These studies suggest that postphagocytic, thiol-mediated reduction in CPR binding may play a physiologic role in the inhibition of PMN chemotaxis at inflammatory sites. The state of CPR-associated thiols may be an important determinant of CPR binding under physiologic conditions other than phagocytosis.

scholarly journals Phagocytosis-induced chemotaxis receptor cycling in neutrophils is mediated by thiol oxidation

Blood ◽  
1982 ◽  
Vol 59 (6) ◽  
pp. 1337-1343 ◽  
Author(s):  
TA Lane ◽  
GE Lamkin
Keyword(s):  
Important Determinant ◽  
Receptor Occupancy ◽  
Thiol Groups ◽  
Thiol Oxidation ◽  
Chemotactic Peptide ◽  
Oxidation Reduction ◽  
Dependent Inhibition ◽  
Dose Dependent ◽  
Physiologic Role ◽  
Mediated Reduction

Abstract We previously demonstrated that neutrophil (PMN) phagocytosis of opsonized zymosan (OPZ) caused oxygen-dependent inhibition of chemotactic peptide receptor (CPR) binding using the ligand 3H-formyl- methionyl-leucyl-phenylalanine (3H-FMLP). In the current studies we sought to determine the mechanism of CPR inhibition by OPZ. We found that 3 mM cysteine and 5 mM dithiothreitol (DTT) did not decrease PMN phagocytosis, but abolished CPR inhibition by OPZ. Furthermore, incubation of PMN with DTT after OPZ partially restored the suppressed CPR. PMN CPR saturation studies with 3H-FMLP on PMN incubated with or without DTT after phagocytosis indicated that DTT restored receptor numbers to 92% +/- 6% of prephagocytosis values and also improved CPR affinity for 3H-FMLP. In additional studies we found that the cell penetrating thiol reagents mercuric chloride (HgCl2), N-ethylmaleimide (NEM), and diamide, but not the nonpenetrating agents p- chloromercuriphenylsulfonic acid and p-chloromercuribenzoate, caused rapid, dose-dependent, DTT-inhibitable suppression of up to 85% CPR binding. CPR inhibition by HgCl2 and NEM was irreversible. PMN CPR saturation studies showed that NEM decreased total receptor numbers, not CPR affinity. The effect of NEM was not inhibited by receptor occupancy at 4 degree C or at 37 degree C. These studies indicate that: (1) intact thiol groups are a requirement for CPR ligand-binding; (2) the thiol groups are presumptively located on the interior side of, or within hydrophobic portions of, the plasma membrane and are not part of the 3H-FMLP binding site; (3) thiol oxidation-reduction induces reversible alteration in CPR binding; (4) phagocytosis-induced modulation of the CPR is due, in part, to thiol oxidation. These studies suggest that postphagocytic, thiol-mediated reduction in CPR binding may play a physiologic role in the inhibition of PMN chemotaxis at inflammatory sites. The state of CPR-associated thiols may be an important determinant of CPR binding under physiologic conditions other than phagocytosis.

Solvation and redox properties of [Co(en)3]3+-[Co(en)3]2+ system

1980 ◽  
Vol 45 (2) ◽  
pp. 335-338 ◽  
Author(s):  
Adéla Kotočová ◽  
Ulrich Mayer
Keyword(s):  
Hydrogen Bond ◽  
Lewis Acid ◽  
Specific Interaction ◽  
Redox Properties ◽  
Solvation Effect ◽  
Interacting Particles ◽  
Acid Base ◽  
Polar Solvents ◽  
Oxidation Reduction ◽  
Solvent Molecules

The solvation effect of a number of nonaqueous polar solvents was studied on the oxidation-reduction properties of the [Co(en)3]3+-[Co(en)3]2+ system. Interactions of these ions with the solvent molecules are discussed in terms of their coordination, which is accompanied by a specific interaction of the Lewis acid-base type, namely formation of a hydrogen bond between the interacting particles. This is the main controlling factor of the redox properties of the studied system.

Feedback Controlled Chemical Reactor with Feed of Two Reaction Components with Spectrophotometric Indication

1994 ◽  
Vol 59 (3) ◽  
pp. 549-557
Author(s):  
František Skopal ◽  
Václav Dušek
Keyword(s):  
Sulfuric Acid ◽  
Negative Feedback ◽  
Chemical Reactor ◽  
Reduction Reactions ◽  
Oxidation Reduction

Theoretical relationships and simplifying conditions have been derived for the feed of two reaction components into a nonisochoric reactor with ideal stirring. The feed of reaction components is controlled by the negative feedback at a constant absorbance of the reaction mixture. The theoretical relationships have been verified using model 2. order oxidation-reduction reactions of Ce(IV)/V(IV) and Fe(III)/V(III) in 1 M sulfuric acid at 20 °C.

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