scholarly journals The role of the thiol group in protein modification with methylglyoxal

2009 ◽  
Vol 74 (8-9) ◽  
pp. 867-883 ◽  
Author(s):  
Jelena Acimovic ◽  
Bojana Stanimirovic ◽  
Ljuba Mandic
Keyword(s):  
Protein Modification ◽  
Time Course ◽  
Thiol Group ◽  
Model Systems ◽  
Cross Linking ◽  
Thiol Groups ◽  
Serum Albumins ◽  
Stable Product ◽  
Protein Cross Linking

Methylglyoxal is a highly reactive ?-oxoaldehyde with elevated production in hyperglycemia. It reacts with nucleophilic Lys and Arg side-chains and N-terminal amino groups causing protein modification. In the present study, the importance of the reaction of the Cys thiol group with methylglyoxal in protein modification, the competitiveness of this reaction with those of amino and guanidine groups, the time course of these reactions and their role and contribution to protein cross-linking were investigated. Human and bovine serum albumins were used as model systems. It was found that despite the very low levels of thiol groups on the surface of the examined protein molecules (approx. 80 times lower than those of amino and guanidino groups), a very high percentage of it reacts (25-85 %). The amount of reacted thiol groups and the rate of the reaction, the time for the reaction to reach equilibrium, the formation of a stable product and the contribution of thiol groups to protein cross-linking depend on the methylglyoxal concentration. The product formed in the reaction of thiol and an insufficient quantity of methylglyoxal (compared to the concentrations of the groups accessible for modification) participates to a significant extent (4 %) to protein cross-linking. Metformin applied in equimolar concentration with methylglyoxal prevents its reaction with amino and guanidino groups but, however, not with thiol groups.

Tridegin, a Novel Peptidic Inhibitor of Factor XIIIa from the Leech, Haementeria ghilianii, Enhances Fibrinolysis In Vitro

1997 ◽  
Vol 77 (05) ◽  
pp. 0959-0963 ◽  
Author(s):  
Lisa Seale ◽  
Sarah Finney ◽  
Roy T Sawyer ◽  
Robert B Wallis
Keyword(s):  
Potent Inhibitor ◽  
Platelet Rich Plasma ◽  
Factor Xiiia ◽  
Cross Linking ◽  
Fibrinolytic Enzymes ◽  
Small Polypeptide ◽  
Tissue Plasminogen ◽  
Protein Cross Linking

SummaryTridegin is a potent inhibitor of factor Xllla from the leech, Haementeria ghilianii, which inhibits protein cross-linking. It modifies plasmin-mediated fibrin degradation as shown by the absence of D-dimer and approximately halves the time for fibrinolysis. Plasma clots formed in the presence of Tridegin lyse more rapidly when either streptokinase, tissue plasminogen activator or hementin is added 2 h after clot formation. The effect of Tridegin is markedly increased if clots are formed from platelet-rich plasma. Platelet-rich plasma clots are lysed much more slowly by the fibrinolytic enzymes used and if Tridegin is present, the rate of lysis returns almost to that of platelet- free clots. These studies indicate the important role of platelets in conferring resistance to commonly used fibrinolytic enzymes and suggest that protein cross-linking is an important step in this effect. Moreover they indicate that Tridegin, a small polypeptide, may have potential as an adjunct to thrombolytic therapy.

scholarly journals Oxidation of human haemoglobin by copper. Mechanism and suggested role of the thiol group of residue β-93

1977 ◽  
Vol 165 (1) ◽  
pp. 141-148 ◽  
Author(s):  
C C Winterbourn ◽  
R W Carrell
Keyword(s):  
Electron Transfer ◽  
Binding Sites ◽  
Equilibrium Dialysis ◽  
Thiol Group ◽  
Thiol Groups ◽  
Human Haemoglobin ◽  
High Affinity ◽  
Rate Determining Step ◽  
Haemoglobin Molecule

Addition of Cu(II) ions to human oxyhaemoglobin caused the rapid oxidation of the haem groups of the beta-chain. Oxidation required binding of Cu(II) to sites involving the thiol group of beta-93 residues and was prevented when these groups were blocked with iodoacetamide or N-ethylmaleimide. Equilibrium-dialysis studies showed three pairs of binding sites, two pairs with high affinity for Cu(II) and one pair with lower affinity. It was the second pair of high-affinity sites that were blocked with iodoacetamide and were involved in haem oxidation. Cu(II) oxidized deoxyhaemoglobin at least ten times as fast as oxyhaemoglobin, and analysis of rates suggested that binding rather than electron transfer was the rate-determining step. No thiol-group oxidation to disulphides occurred during the period of haem oxidation, although it did occur subsequently in the presence of oxygen, or when Cu(II) was added to methaemoglobin. It is proposed that thiol oxidation did not occur because there exists a pathway of electron transfer between the haem group and copper bound to the beta-93 thiol groups. The route for this electron transfer is discussed, as well as the implications as to the function of the beta-93 cysteine in the haemoglobin molecule.

Direct evidence for the role of Maillard reaction products in protein cross-linking in milk powder during storage

2013 ◽  
Vol 31 (2) ◽  
pp. 83-91 ◽  
Author(s):  
Thao T. Le ◽  
John W. Holland ◽  
Bhesh Bhandari ◽  
Paul F. Alewood ◽  
Hilton C. Deeth
Keyword(s):  
Maillard Reaction ◽  
Direct Evidence ◽  
Milk Powder ◽  
Cross Linking ◽  
Maillard Reaction Products ◽  
Reaction Products ◽  
Protein Cross Linking

Chemorheology of Polysulfide Rubbers

1949 ◽  
Vol 22 (3) ◽  
pp. 712-730
Author(s):  
Marcos Mochulsky ◽  
Arthur V. Tobolsky
Keyword(s):  
Molecular Structure ◽  
Exchange Reaction ◽  
Thiol Group ◽  
Cross Linking ◽  
Thiol Groups ◽  
Disulfide Linkage ◽  
Cold Flow ◽  
Adjacent Chain ◽  
Chemical Type ◽  
Chemical Agents

Abstract Experimental results indicate that the socalled “cold flow” of polysulfide rubbers is almost certainly chemical rather than physical in nature. The term chemorheology has been adopted to describe this chemical type of plasticity. The experimental method employed in this investigation was the measurement of relaxation of stress in stretched rubber samples held at a constant elongation. The changes in relaxation rate produced by changing the molecular structure of the rubber (by cross-linking), by incorporating carbon black, by illuminating with ultraviolet light, and by treating the rubber with various chemical agents, such as sulfur, a thiol, and agents that destroy thiol groups, were studied by this method. From the results of the above experiments and from additional considerations, it is concluded that the chemical reaction responsible for cold flow is an intermolecular exchange reaction, and that this exchange reaction is probably an exchange between a terminal thiol group of one chain and a disulfide linkage of an adjacent chain.

scholarly journals Organization of thiol groups of electric-eel electric-organ sodium-plus-potassium ion-stimulated adenosine triphosphatase studied with bifunctional reagents

1980 ◽  
Vol 185 (3) ◽  
pp. 787-790 ◽  
Author(s):  
W E Harris ◽  
W L Stahl
Keyword(s):  
Adenosine Triphosphatase ◽  
Polar Solvent ◽  
Electric Organ ◽  
Thiol Group ◽  
Cross Linking ◽  
Thiol Groups ◽  
High Solubility ◽  
Efficient Inhibitor ◽  
Polar Environment ◽  
Electric Eel

The reactions of three bifunctional thiol-blocking reagents of differing cross-linking spans and two monofunctional thiol-blocking reagents with the Na+ + K+-stimulated ATPase of the electric-eel electric organ were examined. 1,5-Difluoro-2,4-dinitrobenzene with a cross-linking span of 0.3-0.5 nm (3-5 A) and high solubility in non-polar solvent was the most efficient inhibitor of enzyme activity; thus essential thiol groups exist in a non-polar environment and are approx. 0.3-0.5 nm (3-5 A) from their nearest thiol-group neighbours. Ligands promoting phosphorylation of the Na+ + K+-stimulated ATPase decreased the number of thiol groups bridged by 1,5-difluoro-2,4-dinitrobenzene and by 4,4'-difluoro-3,3'-dinitrodiphenyl sulphone [0.7-1.0 nm (7-10 A) span]. Phosphorylation is associated with a conformational change in the enzyme.

The Role of Redox-Active Amino Acids on Compound I Stability, Substrate Oxidation, and Protein Cross-Linking in Yeast CytochromecPeroxidase†

Biochemistry ◽  
2001 ◽  
Vol 40 (49) ◽  
pp. 14942-14951 ◽  
Author(s):  
Thomas D. Pfister ◽  
Alan J. Gengenbach ◽  
Sung Syn ◽  
Yi Lu
Keyword(s):  
Amino Acids ◽  
Substrate Oxidation ◽  
Cross Linking ◽  
Compound I ◽  
Redox Active ◽  
Protein Cross Linking

Role of transglutaminase and protein cross-linking in the repair of mucosal stress erosions

1992 ◽  
Vol 262 (5) ◽  
pp. G818-G825 ◽  
Author(s):  
J. Y. Wang ◽  
L. R. Johnson
Keyword(s):  
Enzyme Activity ◽  
Oral Administration ◽  
Specific Inhibitor ◽  
Duodenal Mucosa ◽  
Mucosal Healing ◽  
Cross Linking ◽  
Xiphoid Process ◽  
Transglutaminase Activity ◽  
Protein Cross Linking

We have recently demonstrated that polyamines are absolutely required for gastric and duodenal mucosal repair after stress. Polyamines act as substrates for transglutaminase and facilitate protein cross-linking. The current study tests whether transglutaminase and protein cross-linking are involved in the mechanism of mucosal healing. Rats were fasted 22 h, placed in restraint cages, and immersed in water to the xiphoid process for 6 h. Animals were killed immediately or 4, 12, or 24 h after stress. Gastric and duodenal mucosa were examined histologically and grossly, and transglutaminase activity was measured. Transglutaminase activity in gastric and duodenal mucosa was increased significantly from 0 to 8 h, peaking 4 h after the 6-h stress period. By 12 h, enzyme activity in duodenal mucosa had returned to control values while gastric mucosal transglutaminase did not decrease to control values until 24 h. Mucosal recovery from lesions produced by stress was evident 12 h after stress and was almost complete by 24 h. Dansylcadaverine (100 mg/kg, orally), a specific inhibitor of protein cross-linking, not only prevented the increases in transglutaminase but significantly decreased healing in both tissues. Oral administration of the polyamine spermidine (100 mg/kg) immediately after stress totally prevented inhibition of repair caused by blocking ornithine decarboxylase with difluoromethylornithine (DFMO, 500 mg/kg). Administration of dansylcadaverine, together with spermidine, significantly prevented the beneficial effect of spermidine on mucosal healing in the DFMO-treated animals.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Analysis of disulphide bond linkage between CoA and protein cysteine thiols during sporulation and in spores of Bacillus species

2020 ◽  
Vol 367 (23) ◽  
Author(s):  
Alexander Zhyvoloup ◽  
Bess Yi Kun Yu ◽  
Jovana Baković ◽  
Mathew Davis-Lunn ◽  
Maria-Armineh Tossounian ◽  
...  
Keyword(s):  
Protein Modification ◽  
Redox Regulation ◽  
Bond Formation ◽  
Thiol Group ◽  
Disulphide Bond ◽  
Bacillus Species ◽  
Spectrometric Analysis ◽  
Disulphide Bond Formation ◽  
Cysteine Thiols

ABSTRACT Spores of Bacillus species have novel properties, which allow them to lie dormant for years and then germinate under favourable conditions. In the current work, the role of a key metabolic integrator, coenzyme A (CoA), in redox regulation of growing cells and during spore formation in Bacillus megaterium and Bacillus subtilis is studied. Exposing these growing cells to oxidising agents or carbon deprivation resulted in extensive covalent protein modification by CoA (termed protein CoAlation), through disulphide bond formation between the CoA thiol group and a protein cysteine. Significant protein CoAlation was observed during sporulation of B. megaterium, and increased largely in parallel with loss of metabolism in spores. Mass spectrometric analysis identified four CoAlated proteins in B. subtilis spores as well as one CoAlated protein in growing B. megaterium cells. All five of these proteins have been identified as moderately abundant in spores. Based on these findings and published studies, protein CoAlation might be involved in facilitating establishment of spores’ metabolic dormancy, and/or protecting sensitive sulfhydryl groups of spore enzymes.

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