Metal Ion Activation ofS-Adenosylmethionine Decarboxylase Reflects Cation Charge Density†

Biochemistry ◽  
2007 ◽  
Vol 46 (27) ◽  
pp. 8172-8180 ◽  
Author(s):  
Zichun J. Lu ◽  
George D. Markham
Keyword(s):  
Charge Density ◽  
Metal Ion ◽  
Ion Activation ◽  
Adenosylmethionine Decarboxylase ◽  
Metal Ion Activation ◽  
Cation Charge

Metal Ion Activation of Dioxygen

1981 ◽  
Vol 9 (3) ◽  
pp. 254-255
Author(s):  
H. A. O. HILL
Keyword(s):  
Metal Ion ◽  
Ion Activation ◽  
Metal Ion Activation

scholarly journals Multiple α-mannosidase activities in mammalian tissues as shown by metal-ion activation

1977 ◽  
Vol 163 (3) ◽  
pp. 557-564 ◽  
Author(s):  
S M Snaith
Keyword(s):  
Metal Ions ◽  
Metal Ion ◽  
Active Enzyme ◽  
Thiol Groups ◽  
Ion Activation ◽  
Ph Values ◽  
Neutral Ph ◽  
Mammalian Tissues ◽  
Different Types ◽  
Metal Ion Activation

1. Four different types of alpha-mannosidase activity were shown to occur in several tissues from the rat. There is the Zn2+-dependent enzyme, active at acidic pH, and three enzymes that are active near to neutral pH. 2. The ‘neutral’ enzymes are activated by Fe2+, Co2+ or Mn2+. 3. Optimum activities for these three enzymes are shown at pH values of 5.2, 6.5 and 7.3. The activity at pH6.5 is the only one evident without metal-ion activation, but activity is enhanced by all three metal ions. The activity at pH 5.2 is seen only in the presence of Fe2+ or Co2+, and the activity at pH7.3 is seen only in the presence of Co2+ or Mn2+ and in a non-chelating buffer medium. 4. The pH6.5-active enzyme is inactivated by EDTA, but activity is restored by excess of metal ion. 5. The enzymes differ markedly in their stability. The pH6.5-active enzyme is very labile and the pH7.3-active enzyme is the most stable. 6. Tissue preparations vary widely in their activity at pH6.5, but where activity is low it can be increased by incubation with one of the activating metal cations. 7. All the enzymes active at neutral pH are inhibited by heavy-metal ions and stabilized to some extent by thiol groups.

scholarly journals Mechanism of Heavy Metal Ion Activation of Phytochelatin (PC) Synthase

2000 ◽  
Vol 275 (40) ◽  
pp. 31451-31459 ◽  
Author(s):  
Olena K. Vatamaniuk ◽  
Stéphane Mari ◽  
Yu-Ping Lu ◽  
Philip A. Rea
Keyword(s):  
Heavy Metal ◽  
Metal Ion ◽  
Heavy Metal Ion ◽  
Ion Activation ◽  
Metal Ion Activation

METAL ION ACTIVATION IN ENZYMATIC CATALYSIS. ARGINASE

1936 ◽  
Vol 58 (12) ◽  
pp. 2654-2655 ◽  
Author(s):  
Leslie Hellerman ◽  
C. Chester Stock
Keyword(s):  
Metal Ion ◽  
Enzymatic Catalysis ◽  
Ion Activation ◽  
Metal Ion Activation
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