Protein oxidation, tyrosine nitration, and inactivation of sarcoplasmic reticulum Ca2+-ATPase in low-frequency stimulated rabbit muscle.
Sustained contractile activity by chronic low-frequency stimulation in rabbit fast-twitch muscle causes a partial (40-50%) inactivation of the sarcoplasmic reticulum (SR) Ca2+-ATPase and, with prolonged stimulation, a SERCA1a to SERCA2a transition. To investigate the underlying mechanism of the inactivation which precedes the isoform transition, we analyzed SR from 4-day stimulated muscles for Ca2+-ATPase activity, lipid peroxidation, SH and carbonyl groups, and nitrotyrosine. At unaltered SH group and malondialdehyde contents, carbonyl groups were elevated 50% in the SR from stimulated muscles. Immunoblotting with anti-dinitrophenyl and anti-nitrotyrosine antibodies revealed strong labeling of the Ca2+-ATPase, suggesting the inactivation of the enzyme to result from protein oxidation and peroxynitrite-mediated tyrosine nitration.
Klebl
B M
BM
Fakultät für Biologie, Universität Konstanz, Constance, Germany.
Ayoub
A T
AT
Pette
D
D
D000818:Animals; D000252:Calcium-Transporting ATPases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D004558:Electric Stimulation; D005609:Free Radicals; D015227:Lipid Peroxidation; D008297:Male; D009119:Muscle Contraction; D017672:Nitrogen Compounds / Q000378:metabolism; D010084:Oxidation-Reduction; D011817:Rabbits; D012519:Sarcoplasmic Reticulum / Q000378:metabolism*; D013438:Sulfhydryl Compounds / Q000378:metabolism; D014443:Tyrosine / Q000378:metabolism*
D005609:Free Radicals; D017672:Nitrogen Compounds; D013438:Sulfhydryl Compounds; D014443:Tyrosine; D000252:Calcium-Transporting ATPases