Oxalate binding to rat kidney mitochondria: induction by oxidized glutathione.

ABSTRACT

Increased oxalate binding with negative correlation with reduced glutathione content was observed during lipid peroxidation in rat kidney mitochondria. In presence of oxidized glutathione (GSSG), peroxidized mitochondria lost 48% of protein-SH with concomitant 3-fold increase in oxalate binding activity while control mitochondria lost only 20% protein-SH with only 0.8 fold increase in oxalate binding activity. The GSSG-induced oxalate binding was apparently due to two-fold increased affinity of oxalate to the protein. Reduced glutathione (GSH) inhibited oxalate binding competitively with Ki, 1.4 x 10(-3) M. Urolithic rat kidney mitochondria showed 30-50% increase in oxalate binding activity along with depletion of GSH and protein-SH. These studies suggest that oxalate binding is regulated by thiol status of mitochondria.