Direct activation of the fat cell n-glucose transport system by the lectin concanavalin A was studied using a rapid filtration procedure which monitors 3-O-[3H]methylglucose uptake in isolated brown fat cells. Transport of this nonmetabolized D-glucose analogue, which occurs by facilitated diffusion, was linear for 5 or more min, temperature-dependent, and inhibited by unlabeled n-glucose, phlo...

The interaction of concanavalin A, the phytohemagglutinin of the jack bean, with a variety of glycosides has been studied by the technique of ultraviolet difference spectroscopy. Whereas methyl a-D-glUC0and manno-pyranoside gave rise to relatively low intensity difference spectra, p-nitrophenyl a-D-mannopyranoside and a-D-glucopyranoside yielded large difference spectra upon interaction with co...

1. A high proportion of the ferritin in normal serum binds to concanavalin A. Binding is prevented by the addition of alpha-D-methylglucoside to the reaction mixture. 2. Ferritin in extracts of normal heart, liver and spleen or serum ferritin from patients with massive hepatic necrosis does not bind to concanavalin A. 3. Isoelectric focusing of preparations of serum ferritin from patients with ...

Ultrastructural analyses have revealed striking similarities between Concanavalin A capping and phagocytosis in leukocytes. Both processes involve extensive membrane movement to form a protuberance or pseudopods; a dense network of microfilaments is recruited into both the protuberance and the pseudopods; microtubules are disassembled either generally (capping) or in the local region of the pse...