Creatine Phosphate as the Preferred Early Indicator of Ischemia in Muscular Tissues

1996 ◽  
Vol 61 (1) ◽  
pp. 227-236 ◽  
Author(s):  
Jiming Ye ◽  
Michael G. Clark ◽  
Eric Q. Colquhoun
1992 ◽  
Vol 68 (05) ◽  
pp. 570-576 ◽  
Author(s):  
Mary A Selak

SummaryWe have previously demonstrated that human neutrophil cathepsin G is a strong platelet agonist that binds to a specific receptor. This work describes the effect of neutrophil elastase on cathepsin G-induced platelet responses. While platelets were not activated by high concentrations of neutrophil elastase by itself, elastase enhanced aggregation, secretion and calcium mobilization induced by low concentrations of cathepsin G. Platelet aggregation and secretion were potentiated in a concentration-dependent manner by neutrophil elastase with maximal responses observable at 200 nM. Enhancement was observed when elastase was preincubated with platelets for time intervals of 10–60 s prior to addition of a low concentration of cathepsin G and required catalytically-active elastase since phenylmethanesulphonyl fluoride-inhibited enzyme failed to potentiate cell activation. Neutrophil elastase potentiation of platelet responses induced by low concentrations of cathepsin G was markedly inhibited by creatine phosphate/creatine phosphokinase and/or indomethacin, indicating that the synergism between elastase and cathepsin G required the participation of ADP and thromboxane A2. On the other hand, platelet responses were not attenuated by the PAF antagonist BN 52021, signifying that PAF-acether did not play a role in elastase potentiation. At higher concentrations porcine pancreatic elastase exhibits similar effects to neutrophil elastase, demonstrating that the effect of elastase was not unique to the neutrophil protease. While neutrophil elastase failed to alter the ability of cathepsin G to hydrolyze a synthetic chromogenic substrate, preincubation of platelets with elastase increased the apparent affinity of cathepsin G binding to platelets. In contrast to their effect on cathepsin G-induced platelet responses, neither neutrophil nor pancreatic elasatse potentiated aggregation or dense granule release initiated by ADP, PAF-acether, arachidonic acid or U46619, a thromboxane A2 mimetic. Moreover, unlike its effect on cathepsin G, neutrophil elastase inhibited thrombin-induced responses. The current observations demonstrate that elastase can potentiate platelet responses mediated by low concentrations of cathepsin G, suggesting that both enzymes may function synergistically to activate platelets under conditions where neutrophil degranulation occurs.


2021 ◽  
Vol 167 ◽  
pp. 105283
Author(s):  
M.A. Primost ◽  
A. Averbuj ◽  
G. Bigatti ◽  
F. Márquez

2020 ◽  
pp. 174751982097858
Author(s):  
M Vraneš ◽  
S Ostojić ◽  
Č Podlipnik ◽  
A Tot

Comparative molecular docking studies on creatine and guanidinoacetic acid, as well as their phosphorylated analogues, creatine phosphate, and phosphorylated guanidinoacetic acid, are investigated. Docking and density functional theory studies are carried out for muscle creatine kinase. The changes in the geometries of the ligands before and after binding to the enzyme are investigated to explain the better binding of guanidinoacetic acid and phosphorylated guanidinoacetic acid compared to creatine and creatine phosphate.


2020 ◽  
Vol 117 ◽  
pp. 106547
Author(s):  
Marta Narváez ◽  
Sonia Cabezas ◽  
Francisco Blanco-Garrido ◽  
Raquel Baos ◽  
Miguel Clavero ◽  
...  

2001 ◽  
Vol 6 (2) ◽  
pp. 117-127 ◽  
Author(s):  
Nuala Beahan ◽  
Joseph Kei ◽  
Clare O'Rourke ◽  
Ravi Sockalingam ◽  
Veronica Smyth ◽  
...  

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