Abstract: | The quenching of the intrinsic protein fluorescence of sarcoplasmic reticulum Ca-ATPase from the rabbit skeletal muscles by hydrophylic (NaI, CsCl) or hydrophobic (pyrene, fluorescamine) substances has been studied. CsCl (up to 1 M) has been shown not to affect the intrinsic protein fluorescence while NaI (250 mM) quenches it at 15%, pyrene (8 mkM) decreases the intrinsic fluorescence of Ca-ATPase at 35% and fluorescamine (up to 40 mkM)--at 80%. Possible mechanisms of the interaction of the quenchers with the intrinsic fluorescence of sarcoplasmic reticulum Ca-ATPase are being discussed. |