Effects of spirogermanium on the in vitro assembly and disassembly of brain microtubules

Abstract The inhibition of microtubule proteins (MTP) assembly by Spirogermanium (SP, 1.25–100 μM) has been studied. Assembly at 37°C was monitored by turbidity measurements and electron microscopy. For SP in 1 : 1 protein-drug ratio the inhibition of assembly was 50%. Addition of 12.5 μM SP to microtubules induced spontaneous disassembly. SP had less effect on the assembly of pure tubulin (tubulin 6S). Complete inhibition of assembly induced by glycerol and Mg 2+ was found with 250 μM and the ratio of SP to tubulin to obtain 50% inhibition was higher than with MTP.