Specificity of Sugar Transport in Trypanosoma gambiense*

SYNOPSIS Some carbohydrates inhibited glucose and fructose transport in Trypanosoma gambiense. Glucose transport was inhibited by glycerol, mannose, 2-deoxy-D-glucose, glucosamine and N-acetylglucosamine. Fructose transport was inhibited by glucose, glycerol, mannose, glucosamine and N-acetylglucosamine. Glucosamine transport appeared to be a mediated process and had a K_m of 1.20 mM and a V_max of 28.5 μM glucosamine/g dry wt/2 min. Glucosamine absorption was competitively inhibited by glucose, fructose and N-acetylglycosamine. N-Acetylglucosamine appeared to enter by passive diffusion. Reciprocal inhibition experiments suggested that glucosamine entered entirely via the “fructose site.” Specificity of sugar transport in T. gambiense differs from that of other organisms.