The presence of lectins in Robinia pseudoacacia root-tip extracts was
demonstrated by horse erythrocyte agglutination and aggregation of (ne
o)glycoprotein-coated beads. Two lectins were purified from a crude pr
otein extract by ion-exchange and affinity chromatography. A mixture o
f lectins was obtained by cation-exchange chromatography on a CM-Trisa
cryl column. Rabinia pseudoacacia root agglutinin II (RPrAII) was furt
her purified by specific elution from a GalNAc-BSA-Sepharose-4B column
. Material passing through the GalNAc-BSA-Sepharose-4B column was stil
l active as determined by erythrocyte agglutination, and aggregated or
osomucoid-coated beads, this material was further purified by affinity
chromatography on an orosomacuoid-Sepharose-4B column. Elution with 5
0 mM HC1 at pH 1.5 led to the purification of the second lectin referr
ed as Rabinia pseuctoacacia root agglutinin I (RPrAI). Biochemical ana
lysis suggests that RPrAI is a heterodimer made up of M(r)29 000 and 3
1 000 subunits whereas RPrAII is a homodimer made up of M(r) 30 000 su
bunits, and that both lectins are glycoproteins. N-terminal sequences
were determined for both lectins and compared with those deduced from
cDNA clones encoding bark and seed lectins. Our results suggest that r
oot lectins are not strictly identical with, but closely related to th
e Robinia pseudoacacia seed and bark lectins. (C) 1997 Elsevier Scienc
e Ireland Ltd.