Mannose does not compete well for ConA binding.  You will have better luck with
alpha methyl mannoside  (in the millimolar range).  Instead of using a simple
sugar you migh also try a large molecular weight mannan.  Mannan is available
from sigma (baker's yeast mannan).  For me at least, the binding of ConA is
pretty slow, so you might try a lengthy preincubation of the ConA with the
competing substances.
 
In message <[log in to unmask]> Confocal Microscopy List writes:
> I am looking for some advice on lectin protocols.  I am currently binding a
> FITC-conjugated lectin to the symbiosome membrane surrounding an
> endosymbiotic algal cell that has been extracted from the anemone host
> cell.  I have had good success in binding the lectins to the membrane,
> but have had NO success in inhibiting the binding through the use of a
> competing sugar.  According to published literature, the addition of a
> competing sugar to the lectin solution prior to the addition of the
> algal cells should prohibit binding to the membrane.  Well, it just isn't
> happening.  I have tried varying the concentration of lectin and sugar
> and this does not seem to have an effect.  The lectin that I am currently
> working with is succinylated-Concanavalin A and it's competing sugar,
> mannose.
>
> All helpful suggestions will be appreciated.
>
> tim wakefield
 
 
 
  _____________________________________________________________
 / Michael J. Herron  University of MN,  Dept. of Dermatology /
/ [log in to unmask]                                 /
_____________________________________________________________