help needed purification asolectin from fluorescence

[zeljkos at vms.ucc.okstate.edu]

HELP NEEDED IN PURIFICATION OF ASOLECTIN FROM 
FLUORESCENT IMPURITIES
My problem is that I am not able to get rid of fluorescent impurities in 
asolectin. It was purchased from Associated Concentrates (New York) in 
1988. If to excite at 280-320, significant fluorescent background appears 
in
 the region 320-400 nm . Hundred micrograms of asolectin suspended in 1 
ml 
of water give background of about 0.2 ( slit widths 5 and 5 nm, Perkin-
Elmer 
650-40). Almost the same picture is observed in hexane. I would like to 
reduce it to 0.02. Standard acetone washing makes only slight difference. 
Ether/ethanol wash (including dissolving in ether with following 
precipitation by ethanol) does not likely change background level. If 
somebody is familiar with this problem I shall greatly appreciate any 
information.
 tolkach at okway.okstate.edu