Identification of the catalytic site of rat liver glutathione peroxidase as selenocysteine

Biochemistry ◽  
1978 ◽  
Vol 17 (13) ◽  
pp. 2639-2644 ◽  
Author(s):  
John W. Forstrom ◽  
Jack J. Zakowski ◽  
Al L. Tappel
Keyword(s):  
Glutathione Peroxidase ◽  
Rat Liver ◽  
Catalytic Site ◽  
Liver Glutathione

Influence of mercury (II), cadmium (II), methylmercury, and phenylmercury on the kinetic properties of rat liver glutathione peroxidase

1985 ◽  
Vol 63 (12) ◽  
pp. 1212-1216 ◽  
Author(s):  
E. M. Bem ◽  
K. Mailer ◽  
C. M. Elson
Keyword(s):  
Glutathione Peroxidase ◽  
Rat Liver ◽  
Rate Constants ◽  
Metal Binding ◽  
Quaternary Structure ◽  
Kinetic Properties ◽  
Inhibition Rate ◽  
Liver Glutathione ◽  
Mercury Compounds ◽  
Mercury Salts

The effect of phenylmercury and methylmercury on rat liver glutathione peroxidase (GSH Px) is investigated and compared with that of Hg(II) and with some previously reported results for Cd(II). Analysis of the kinetics of metal binding to the enzyme gives apparent inhibition rate constants: kc = 9.7 mM−1 min−1 for all three mercury compounds and 75 mM−1 min−1 for CdCl2. Glutathione (0.2 mM) protects the enzyme from metal inhibition, decreasing the apparent inhibition rate constants (kc) by 3.6 times for mercury compounds and 4.4 times for CdCl2. K1 for the three mercury compounds is found to be 53 μM. It is unexpected that the same value of K1 exists for all three forms of mercury studied and that inhibition of the enzyme by the metals is a relatively slow process. For Cd(II) the value of K1 is 8.5 μM. It is suggested that inhibition of GSH·Px enzyme activity by cadmium, mercury, and organic mercury salts may not be due to simple complexation of the active site selenium moiety but may be due to a slower process, e.g., an alteration of the enzyme tertiary or quaternary structure.

Rat liver glutathione peroxidase: Purification and study of multiple forms

1977 ◽  
Vol 183 (2) ◽  
pp. 490-497 ◽  
Author(s):  
Fred H. Stults ◽  
John W. Forstrom ◽  
Danny T.Y. Chiu ◽  
Al L. Tappel
Keyword(s):  
Glutathione Peroxidase ◽  
Rat Liver ◽  
Multiple Forms ◽  
Liver Glutathione
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