FIGURE 6.

Effects of extracellular Ca²⁺ and Mg²⁺ on activities of released ATPases and ADPases. (A–D) eATP hydrolysis by soluble enzymes in controls (KBS) and mKBS: panel (A) shows the decrease of eATP and panels (B–D) show the increase in eADP, eAMP, and eADO formed from eATP, respectively. (E–G) eADP hydrolysis by soluble enzymes in control (KBS) and mKBS: panel (E) shows eADP decrease and panels (F,G) show the increase in eAMP and eADO formed from eADP. KBS contains normal Ca²⁺ (1.8 mM) and Mg²⁺ (1.2 mM). mKBS-A contains normal Ca²⁺ (1.8 mM) and no Mg²⁺ (0 mM); mKBS-B contains 0 mM Ca²⁺, normal Mg²⁺ (1.2 mM), and EGTA (5 mM); mKBS-C contains 0 mM Ca²⁺, 0 mM Mg²⁺, and EGTA (5 mM); mKBS-D contains 0 mM Ca²⁺, normal Mg²⁺ (1.2 mM), EGTA (5 mM), and EDTA (5 mM); mKBS-E contains 0 mM Ca²⁺, 0 mM Mg²⁺, EGTA (5 mM), and EDTA (5 mM). Asterisks denote significant difference from controls (KBS). *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001.