Lectins are not as specific as widely believed, ie, compared to
antibodies...there are a range of binding affinities by different sugars
for most lectins.  In particular, mannose is definitely not the only
sugar affinity for Con A.  Your ConA binding in the presence of mannose
may be due to one of the others.  You can find some likely candidates in
the carbohydrate chemistry literature.  The histochem. literature is not
particularly reliable for this type of screening.  If all else fails,
call one of the main labs working on lectins.  One possibility is Irwin
Goldstein's lab, Biochemistry, Univ. Michigan, Ann Arbor (don't know
phone number)....Good luck.
 
On Tue, 24 Jan 1995, Timothy S Wakefield wrote:
 
> 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
>