Wanted Lectin A of Lens culinary

[XYZZYX at DELPHI.COM]

hi, it's george again.  Thought I'd follow up with a little more info.  I 
had a Sigma catalog out today, so I checked their entry for Lens 
culinaris lectin.  Unfortunately, the stuff they sell is a mixture of 
A+B.  The lectin occurs naturally as a dimer of A+B, which probably 
explains why that is all that most people seem to sell.  I tried to pull 
down a sequence for each from the various databases but was unsuccessful; 
only one sequence appears.  Both isolectins have the same approximate Mr 
(49000) but (I think) differ in isoelectric points.  I'm not sure if they 
are disulfide linked (run some on a gel +/- BME, that ought to show it).  
Both isolectins have affinity for terminal 
alpha-D-mannose and alpha-D-glucose so it probably won't work to run an 
affinity column to separate them.  Ion exchange chromatography or 
Hydrophobic interaction chromatography might work (and HIC is a nice 
follow on step to Ammonium sulfate pptn., as well), though I would still 
recommend an initial separation on a sugar column (e.g. mannose-agarose) 
to get a reasonably pure material first.  There was one reference listed 
in the sigma catalog: Howard, I.K., et al.,J. Biol. Chem., 246, 1590 (1971).

Good luck.