Purified acetylcholinesterase from toluene‐treated organs of the electric eel (form B) was inhibited in a noncompetitive manner by the acridine derivatives proflavine and acriflavine. With proflavine secondary plots of slopes and intercepts revealed hyperbolic inhibition patterns. The secondary plots of acriflavine showed a biphasic inhibition pattern with two different slopes (slope1 > slope2). A similar biphasic inhibition pattern was observed in the Dixon plot. From the two slopes two apparent Ki‐values were obtained. Between 0 and 1 μM acriflavine (low concentrations of acriflavine) the apparent inhibition constant was 0.6 μM, at acriflavine concentrations greater than 1 μM (high concentrations of acriflavine) the apparent inhibition constant was 2.2 μM. The apparent Km values for acetylthiocholine were 52 μM and 99 μM respectively. The relative V were 0.37 IU and 0.26 IU respectively. At high concentrations of acriflavine the double‐reciprocal plot of substrate concentration versus enzyme activity became hyperbolic and the Hill coefficient for acetylthiocholine was 0.6. However, in presence of 2 mM hexamethonium it increased to 0.9. Double inhibitor studies were carried o
📖 افتح في inklap 🔗 DOI 📮 اطلب بحثاً