Mitochondrial sulfhydryl groups. A possible endogenous probe of conformational changes in the mitochondrial membrane.
The protein-bound sulfhydryl (SH) groups of the mitochondrial membrane were determined with Ellman's reagent in energized and non-energized configurational states of mitochondria and submitochondrial particles. When beef heart mitochondria were energized by respiration, there was a decrease in titratable protein-bound SH groups which varied according to substrate: NADH-linked substrates induced a decrease of about 10 nmol per mg of protein,succinate about 7, and ascorbate-tetramethyl-p-phenylene-diamine about 3. Similar changes occurred in phosphorylating submitochondrial particles. A decrease in SH titer was also observed in non-energized conditions, induced by hypotonic treatment and by some reagents inhibiting electron transport and oxidative phosphorylation and inducing orthodox configuration. These changes in protein-bound SH groups might be useful in analyzing the conformational states of mitochondrial membranes.
D000818:Animals; D002417:Cattle; D002642:Chick Embryo; D007700:Kinetics; D008566:Membranes / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D008929:Mitochondria, Heart / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure*; D009124:Muscle Proteins / Q000032:analysis* / Q000378:metabolism; D009994:Osmolar Concentration; D010710:Phosphates / Q000494:pharmacology; D012402:Rotenone / Q000494:pharmacology; D013438:Sulfhydryl Compounds / Q000032:analysis*; D014475:Uncoupling Agents / Q000494:pharmacology
D009124:Muscle Proteins; D010710:Phosphates; D013438:Sulfhydryl Compounds; D014475:Uncoupling Agents; D012402:Rotenone