The concentration of ionized magnesium in barnacle muscle fibres.
1. The total Mg in isolated fibres of Balanus aquila was 10-5 m-mole/kg wet wt. 2. The intracellular free Mg was measured by a null point method using Eriochrome Blue as an indicator of free Mg, and internal dialysis with solutions of varying ionized Mg concentrations. The results indicated a free Mg of 6 mM or 4-2 m-mole/kg wet wt. in the intracellular water immediately surrounding the dialysis capillary. 3. The ATP concentration was estimated to be 4-9 m-mole/kg wet wt. 4. A tentative partitioning of Mg among various intracellular constitutents based on present data combined with published work by others is (m-mole/kg wet wt): free, 4-2; MgATP, 4-2; myofibrillar bound, 1; residual (presumably bound to arginine phosphate and phosphate) ca. 1.
The concentration of ionized magnesium in barnacle muscle fibres. 1. The total Mg in isolated fibres of Balanus aquila was 10-5 m-mole/kg wet wt. 2. The intracellular free Mg was measured by a null point method using Eriochrome Blue as an indicator of free Mg, and internal dialysis with solutions of varying ionized Mg concentrations. The results indicated a free Mg of 6 mM or 4-2 m-mole/kg wet wt. in the intracellular water immediately surrounding the dialysis capillary. 3. The ATP concentration was estimated to be 4-9 m-mole/kg wet wt. 4. A tentative partitioning of Mg among various intracellular constitutents based on present data combined with published work by others is (m-mole/kg wet wt): free, 4-2; MgATP, 4-2; myofibrillar bound, 1; residual (presumably bound to arginine phosphate and phosphate) ca. 1.