Effect of extremely low frequency magnetic fields on calpain activation.
The effects of low intensity, low frequency magnetic fields (MFs) on catalytic activity of the calcium dependent protease calpain was determined following the enzyme activation both in "in vitro" and "in vivo" conditions. We have observed that a 0.3 mT MF induces a significant increase in the requirement of the protease for this metal ion. This change is detectable at low [Ca(2+)] and disappears when the level of Ca(2+) is raised to saturating amounts. The observed effects are not due to transient MF(-) induced conformational changes occurring in calpain, but to direct effects of the MF on Ca(2+) ions, which become less available for the binding sites present in calpain. Altogether, these results indicate that exposure to low intensity, low frequency MFs alters the intracellular Ca(2+) "availability," thereby modifying the related cell response.
Salamino
Franca
F
Department of Experimental Medicine-Biochemistry Section, and Centre of Excellence for Biomedical Research, University of Genoa, Viale Benedetto XV, Italy.
Minafra
Roberto
R
Grano
Valentina
V
Diano
Nadia
N
Mita
Damiano Gustavo
DG
Pontremoli
Sandro
S
Melloni
Edon
E
D000818:Animals; D001457:Anion Exchange Protein 1, Erythrocyte / Q000378:metabolism; D002118:Calcium / Q000494:pharmacology; D002135:Calcium-Binding Proteins / Q000494:pharmacology; D002154:Calpain / Q000037:antagonists & inhibitors / Q000378:metabolism*; D004574:Electromagnetic Fields; D004789:Enzyme Activation; D004912:Erythrocytes / Q000201:enzymology; D006461:Hemolysis; D006801:Humans; D051381:Rats
D001457:Anion Exchange Protein 1, Erythrocyte; D002135:Calcium-Binding Proteins; C033668:calpastatin; D002154:Calpain; D002118:Calcium