TY - JOUR
T1 - Effect of Ca2+ and Mg2+ on the Mn-superoxide dismutase from rat liver and heart mitochondria
AU - Pérez-Vázquez, V.
AU - Ramírez, J.
AU - Aguilera-Aguirre, L.
AU - González-Hernández, J. C.
AU - Clemente-Guerrero, M.
AU - Manzo-Ávalos, S.
AU - Uribe, S.
AU - Saavedra-Molina, A.
PY - 2002
Y1 - 2002
N2 - The manganese superoxide dismutase (Mn-SOD) converts super-oxide anions to hydrogen peroxide plus oxygen, providing the first line of defense against oxidative stress in mitochondria. Heart mitochondria exhibited higher Mn-SOD activity than liver mitochondria. In mitochondria from both tissues Mn-SOD activity decreased after incubation at low oxygen concentration (hypoxic mitochondria). The effects of free Ca2+ ([Ca2+]f) and free Mg2+ ([Mg2+]f) on normoxic and hypoxic mitochondria from either organ were tested. In normoxic mitochondria from either tissue, both [Ca2+]f and [Mg2+]f activated the enzyme, although [Mg2+]f was less efficient as an activator and the effect was lower in heart than in liver mitochondria. When added simultaneously, high [Ca2+]f and [Mg2+]f exhibited additive effects which were more pronounced in heart mitochondria and were observed regardless of whether mitochondria had been incubated under normal or low oxygen. The data suggest that [Ca2+]f plays a role in regulating Mn-SOD in concert with the activation of aerobic metabolism.
AB - The manganese superoxide dismutase (Mn-SOD) converts super-oxide anions to hydrogen peroxide plus oxygen, providing the first line of defense against oxidative stress in mitochondria. Heart mitochondria exhibited higher Mn-SOD activity than liver mitochondria. In mitochondria from both tissues Mn-SOD activity decreased after incubation at low oxygen concentration (hypoxic mitochondria). The effects of free Ca2+ ([Ca2+]f) and free Mg2+ ([Mg2+]f) on normoxic and hypoxic mitochondria from either organ were tested. In normoxic mitochondria from either tissue, both [Ca2+]f and [Mg2+]f activated the enzyme, although [Mg2+]f was less efficient as an activator and the effect was lower in heart than in liver mitochondria. When added simultaneously, high [Ca2+]f and [Mg2+]f exhibited additive effects which were more pronounced in heart mitochondria and were observed regardless of whether mitochondria had been incubated under normal or low oxygen. The data suggest that [Ca2+]f plays a role in regulating Mn-SOD in concert with the activation of aerobic metabolism.
KW - Amino acids
KW - Calcium
KW - Heart mitochondria
KW - Liver mitochondria
KW - Magnesium
KW - Mn-SOD
KW - Superoxide anion
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UR - http://www.scopus.com/inward/citedby.url?scp=0036278233&partnerID=8YFLogxK
U2 - 10.1007/s007260200024
DO - 10.1007/s007260200024
M3 - Article
C2 - 12107766
AN - SCOPUS:0036278233
SN - 0939-4451
VL - 22
SP - 405
EP - 416
JO - Amino Acids
JF - Amino Acids
IS - 4
ER -