Change in rate-limiting step in proton removal from an intramolecularly hydrogen-bonded acid and the rate of opening and closing of a hydrogen bond

1985 ◽  
Vol 107 (23) ◽  
pp. 6712-6714 ◽  
Author(s):  
N. E. Briffett ◽  
Frank Hibbert ◽  
R. J. Sellens
Keyword(s):  
Hydrogen Bond ◽  
Rate Limiting Step ◽  
Limiting Step ◽  
Opening And Closing ◽  
Rate Limiting ◽  
Hydrogen Bonded

Isotope effect studies of the decomposition of 2-propanol on hafnium(IV) oxide

1977 ◽  
Vol 55 (1) ◽  
pp. 153-157
Author(s):  
Ian M. Hoodless
Keyword(s):  
Hydrogen Bond ◽  
Isotope Effect ◽  
Catalytic Decomposition ◽  
Hafnium Dioxide ◽  
Small Extent ◽  
Dehydrogenation Reaction ◽  
Rate Limiting Step ◽  
Limiting Step ◽  
Major Reaction ◽  
Rate Limiting

The catalytic decomposition of 2-propanol on hafnium dioxide has been investigated over the temperature range 355–397 °C by a micropulse reactor technique. The major reaction is one of dehydration to propene but dehydrogenation also occurs to a small extent. Isotope effect measurements with deuterio-2-propanols indicate that the rate-limiting step in dehydration involves cleavage of the β-carbon-hydrogen while in the dehydrogenation reaction it is cleavage of the α-carbon-hydrogen bond.

Ornithine Decarboxylase Activity in Cultured Endothelial Cells Stimulated by Serum, Thrombin and Serotonin

1978 ◽  
Vol 39 (02) ◽  
pp. 496-503 ◽  
Author(s):  
P A D’Amore ◽  
H B Hechtman ◽  
D Shepro
Keyword(s):  
Endothelial Cells ◽  
Ornithine Decarboxylase ◽  
Decarboxylase Activity ◽  
Aortic Endothelial Cells ◽  
Ornithine Decarboxylase Activity ◽  
Rate Limiting Step ◽  
Bovine Aortic Endothelial Cells ◽  
Limiting Step ◽  
Rate Limiting ◽  
Serum Serotonin

SummaryOrnithine decarboxylase (ODC) activity, the rate-limiting step in the synthesis of polyamines, can be demonstrated in cultured, bovine, aortic endothelial cells (EC). Serum, serotonin and thrombin produce a rise in ODC activity. The serotonin-induced ODC activity is significantly blocked by imipramine (10-5 M) or Lilly 11 0140 (10-6M). Preincubation of EC with these blockers together almost completely depresses the 5-HT-stimulated ODC activity. These observations suggest a manner by which platelets may maintain EC structural and metabolic soundness.

Dynamics of hepatic and peripheral insulin effects suggest common rate-limiting step in vivo

Diabetes ◽  
1993 ◽  
Vol 42 (2) ◽  
pp. 296-306 ◽  
Author(s):  
D. C. Bradley ◽  
R. A. Poulin ◽  
R. N. Bergman
Keyword(s):  
Rate Limiting Step ◽  
Limiting Step ◽  
Rate Limiting

Kinetics of cyclization of S-ethoxycarbonylmethylisothiouronium chloride to 2-imino-4-thiazolidone

1979 ◽  
Vol 44 (3) ◽  
pp. 912-917 ◽  
Author(s):  
Vladimír Macháček ◽  
Said A. El-bahai ◽  
Vojeslav Štěrba
Keyword(s):  
Hydrochloric Acid ◽  
Dilute Hydrochloric Acid ◽  
Base Catalysis ◽  
General Base ◽  
Rate Limiting Step ◽  
Limiting Step ◽  
Kinetics Of Formation ◽  
Acid Catalyzed ◽  
Rate Limiting ◽  
Kinetics Of

Kinetics of formation of 2-imino-4-thiazolidone from S-ethoxycarbonylmethylisothiouronium chloride has been studied in aqueous buffers and dilute hydrochloric acid. The reaction is subject to general base catalysis, the β value being 0.65. Its rate limiting step consists in acid-catalyzed splitting off of ethoxide ion from dipolar tetrahedral intermediate. At pH < 2 formation of this intermediate becomes rate-limiting; rate constant of its formation is 2 . 104 s-1.

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