scholarly journals Site-Specific Protonation Kinetics of Acidic Side Chains in Proteins Determined by pH-Dependent Carboxyl 13C NMR Relaxation

2015 ◽  
Vol 137 (8) ◽  
pp. 3093-3101 ◽  
Author(s):  
Johan Wallerstein ◽  
Ulrich Weininger ◽  
M. Ashhar I. Khan ◽  
Sara Linse ◽  
Mikael Akke
Keyword(s):  
13C Nmr ◽  
Nmr Relaxation ◽  
Side Chains ◽  
Site Specific ◽  
Ph Dependent ◽  
Kinetics Of

Iodoacetate inactivation of rape alcohol dehydrogenase

1980 ◽  
Vol 45 (5) ◽  
pp. 1601-1607 ◽  
Author(s):  
Marie Stiborová ◽  
Sylva Leblová
Keyword(s):  
Alcohol Dehydrogenase ◽  
Protein Molecule ◽  
Sulfhydryl Groups ◽  
Inactivation Rate ◽  
First Order ◽  
Ph Dependent ◽  
Kinetics Of

Iodoacetate inactivates rape alcohol dehydrogenase (ADH, EC 1.1.1.1). The inactivation rate follows the kinetics of the first order, is pH-dependent, and decreases below pH 7.5. Besides irreversible alkylation of the sulfhydryl groups of the enzyme iodoacetate also forms a reversible complex with rape ADH. The coenzyme (NAD) and its analogs (ATP, ADP, AMP) competitively protect the enzyme against alkylation; o-phenanthroline also protects the enzyme against alkylation yet noncompetitively with respect to iodoacetate. Imidazole and o-phenanthroline compete with one another for binding to the protein molecule of rape ADH. Whereas o-phenanthroline decreases the inactivation rate imidazole increases the rate of iodoacetate inactivation.

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