Intramolecular general acid catalysis in the binding reactions of α2 and complement components C3 and C4

1981 ◽  
Vol 1 (6) ◽  
pp. 461-468 ◽  
Author(s):  
Stephen G. Davies ◽  
Robert B. Sim
Keyword(s):  
Acid Catalysis ◽  
Bond Cleavage ◽  
Covalent Binding ◽  
Limited Proteolysis ◽  
Peptide Bond ◽  
Complement Components ◽  
Peptide Bond Cleavage ◽  
Α2 Macroglobulin ◽  
Internal Peptide ◽  
The Complement System

The complement system proteins C3 and C4 and the plasma protease inhibitor α2-macroglobulin~ when activated by limited proteolysis, can bind covalently to other macromolecules. The three proteins also exhibit an unusual internal peptide-bond cleavage reaction when denatured. The covalent binding reaction is likely to occur by a transacylation mechanism involving an internal thioiester in the three proteins. However, the activated species of these proteins are much more reactive than simple thiolesters. Studies of molecular models of the thiolester region in C3 show that an intramolecular acid catalysis mechanism can both account for the exceptional reactivity of the activated form of these proteins and provide an explanation for the denaturation-induced peptide bond cleavage.

scholarly journals Serine protease dynamics revealed by NMR analysis of the thrombin-thrombomodulin complex

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Riley B. Peacock ◽  
Taylor McGrann ◽  
Marco Tonelli ◽  
Elizabeth A. Komives
Keyword(s):  
Active Site ◽  
Serine Proteases ◽  
Protein C ◽  
Catalytic Mechanism ◽  
Bond Cleavage ◽  
Peptide Bond ◽  
Peptide Bond Cleavage ◽  
Exchange Mass Spectrometry ◽  
Catalytically Active ◽  
Hydrogen Deuterium

AbstractSerine proteases catalyze a multi-step covalent catalytic mechanism of peptide bond cleavage. It has long been assumed that serine proteases including thrombin carry-out catalysis without significant conformational rearrangement of their stable two-β-barrel structure. We present nuclear magnetic resonance (NMR) and hydrogen deuterium exchange mass spectrometry (HDX-MS) experiments on the thrombin-thrombomodulin (TM) complex. Thrombin promotes procoagulative fibrinogen cleavage when fibrinogen engages both the anion binding exosite 1 (ABE1) and the active site. It is thought that TM promotes cleavage of protein C by engaging ABE1 in a similar manner as fibrinogen. Thus, the thrombin-TM complex may represent the catalytically active, ABE1-engaged thrombin. Compared to apo- and active site inhibited-thrombin, we show that thrombin-TM has reduced μs-ms dynamics in the substrate binding (S1) pocket consistent with its known acceleration of protein C binding. Thrombin-TM has increased μs-ms dynamics in a β-strand connecting the TM binding site to the catalytic aspartate. Finally, thrombin-TM had doublet peaks indicative of dynamics that are slow on the NMR timescale in residues along the interface between the two β-barrels. Such dynamics may be responsible for facilitating the N-terminal product release and water molecule entry that are required for hydrolysis of the acyl-enzyme intermediate.

Activation of Bovine Factor V by Thrombin and A Protease From Russell's Viper Venom (RVV)

1979 ◽  
Author(s):  
M.J. Lindhout ◽  
C. M. Jackson
Keyword(s):  
Bond Cleavage ◽  
Peptide Bond ◽  
Ion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Factor V ◽  
Peptide Bond Cleavage ◽  
Prothrombinase Complex ◽  
Factor Va ◽  
Activation Products ◽  
Ca Oxalate

In order to understand the function of activated factor V in the prothrombinase complex, we isolated the activation products obtained by action of thrombin and RVV-V on factor V and studied their functional properties. Factor V isolated from plasma by means of ion-exchange chromatography, a Ca-oxalate adsorption step and gelfiltration was homogenous in SDS-gelelectrophoresis (apparent MW 360,000, with and without reduction). Increase in factor V activity upon action by RVV-V is correlated with a single peptide bond cleavage, resulting in a 270,000 dalton and a 80,000 dalton component. Additional proteolysis of factor Va(RVV/V)’ by thrombin results in a further cleavage of the high MW component into peptides with MW's of 72,000, 94,000 and about 150,000 without a furth~r increase in factor V activity. Whereas none of the isolated peptides reveal factor Va activity, activity would be generated by a recombination in the presence of Ca2+ of the 94,000 MW or 270,000 MW component with the 80,000 component. Action of thrombin alone on factor V results in peptides of MW 72,000, 80,000, 94,000 and a peptide very rich in carbohydrate with an apparent MW of 150,000.

Demasking kinetics of peptide bond cleavage for whey protein isolate hydrolysed by Bacillus licheniformis protease

2016 ◽  
Vol 133 ◽  
pp. S426-S431 ◽  
Author(s):  
Mikhail M. Vorob’ev ◽  
Claire I. Butré ◽  
Stefano Sforza ◽  
Peter A. Wierenga ◽  
Harry Gruppen
Keyword(s):  
Whey Protein ◽  
Bacillus Licheniformis ◽  
Bond Cleavage ◽  
Peptide Bond ◽  
Whey Protein Isolate ◽  
Protein Isolate ◽  
Peptide Bond Cleavage ◽  
Kinetics Of

ChemInform Abstract: Unusual Peptide Bond Cleavage Reactions During Acidolytic Deprotection Reactions.

ChemInform ◽  
2010 ◽  
Vol 24 (28) ◽  
pp. no-no
Author(s):  
J. R. SPENCER ◽  
N. G. J. DELAET ◽  
A. TOY-PALMER ◽  
V. V. ANTONENKO ◽  
M. GOODMAN
Keyword(s):  
Bond Cleavage ◽  
Peptide Bond ◽  
Peptide Bond Cleavage ◽  
Cleavage Reactions

scholarly journals Specific peptide-bond cleavage by microwave irradiation in weak acid solution

1992 ◽  
Vol 11 (1) ◽  
pp. 45-50 ◽  
Author(s):  
Chi-Yue Wu ◽  
Shui-Tein Chen ◽  
Shyh-Horng Chiou ◽  
Kung-Tsung Wang
Keyword(s):  
Microwave Irradiation ◽  
Acid Solution ◽  
Bond Cleavage ◽  
Peptide Bond ◽  
Weak Acid ◽  
Peptide Bond Cleavage ◽  
Specific Peptide

scholarly journals Rabbit tissue peptidases that hydrolyse the peptide hormone bradykinin. Differences in enzymic properties and concentration in rabbit tissues

1977 ◽  
Vol 163 (3) ◽  
pp. 433-439 ◽  
Author(s):  
M A Cicilini ◽  
H Caldo ◽  
J D Berti ◽  
A C M Camargo
Keyword(s):  
Bond Cleavage ◽  
Peptide Hormone ◽  
Peptide Bond ◽  
Peptide Bond Cleavage ◽  
Wide Range ◽  
Tissue Homogenates ◽  
Amino Acid Analyser ◽  
Different Tissues ◽  
Rabbit Tissues ◽  
Bradykinin Inactivation

The distribution and properties of neutral peptidases acting on the peptide hormone bradykinin (Arg-Pro-Pro-Gly-Phe-Ser-Pro-Phe-Arg) were determined in several rabbit tissues. The supernatant and particulate fractions prepared from tissue homogenates (25000g for 60min) were studied. Bradykinin inactivation (kininase activity) was measured by bioassay with the isolated guinea-pig ileum. The sites of peptide-bond cleavage were determined in the amino acid analyser, which permits detection and measurement of amino acids and peptides derived from bradykinin. The results indicate that kininases are present in a wide range of concentrations in different tissues, kidney and lung having the most activity. Kininases present in different tissues were distinguished on the basis of sensitivity to the effects of EDTA, dithiothreitol and ZnCl2 and by the site of peptide-bond hydrolysis in bradykinin.

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