Effect of Colchicine on Cell Membrane and on Biopterin Transport in Crithidia fasciculata*

Publisher Website
Google Scholar
Abstract
SYNOPSIS. Incorporation of 14C‐labeled biopterin into Crithidia fasciculata was inhibited by 1 mM colchicine or lumicolchicine. These substances do not penetrate the cell membrane, hence they cannot interact with the subpellicular microtubules. In view of this, interference of colchicine with biopterin transport must occur on the outer surface of the cell membrane. Binding of colchicine to Crithidia was not temperature‐dependent and did not exhibit saturation kinetics. These facts exclude a binding as in the case of tubulin, or similar proteins which may be present in the membrane. The results suggest an inhibition reflecting steric hindrance of the biopterin carrier system.