title: Effects of wheat germ agglutinin on membrane transport.
abstract: (1) Low concentrations of wheat germ agglutinin are cytotoxic toward several tissue culture lines, including Chinese hamster ovary cells, Swiss 3T3 cells, mouse L cells and baby hamster kidney cells. The LD50 ranged from 1 to 5 microgram wheat germ agglutinin per ml. Similar concentrations of the lectin inhibited the transport of the non-utilizable amino acids alpha-aminoisobutyric acid and cycloleucine and inhibited the uptake of thymidine. In contrast, 2-deoxy-D-glucose uptake was not altered and colchicine uptake was enhanced. (2) The inhibition of alpha-aminoisobutyric acid uptake occurred within minutes after lectin addition and was maximal by 1 h. Maximal inhibition ranged from 50 to 70% of control values. Studies of the kinetics of the uptake demonstrated that wheat germ agglutinin decreased the V of the uptake by 70% without affecting the apparent Km. Ovomucoid, a haptene inhibitor of wheat germ agglutinin-binding to cell surface receptors, prevented the wheat germ agglutinin-induced inhibition of alpha-aminoisobutyric acid transport. Three other lectins (Concanavalin A, Phaseolus vulgaris E-phytohemagglutinin and L-phytohemagglutinin) inhibited the uptake by 20% or less at doses up to 50 microgram/ml. (3) We propose that the cytotoxicity of wheat germ agglutinin probably results in part, if not totally, from membrane alterations which impair multiple membrane transport systems.
mesh_terms: D000621:Aminoisobutyric Acids / Q000378:metabolism; D000818:Animals; D001693:Biological Transport, Active; D002460:Cell Line; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism*; D003078:Colchicine / Q000378:metabolism; D006224:Cricetinae; D003515:Cycloleucine / Q000378:metabolism; D003602:Cytotoxicity, Immunologic; D003847:Deoxyglucose / Q000378:metabolism; D037102:Lectins / Q000494:pharmacology*; D051379:Mice; D037121:Plant Lectins; D013936:Thymidine / Q000378:metabolism; D014908:Triticum / Q000276:immunology
chemical_list: D000621:Aminoisobutyric Acids; D037102:Lectins; D037121:Plant Lectins; D003515:Cycloleucine; D003847:Deoxyglucose; D003078:Colchicine; D013936:Thymidine