Comparative studies of carbohydrate-binding proteins from Xenopus laevis skin and eggs. Sugar-binding specificities and affinity purification.
Salt and detergent extracts of acetone-dried powder of Xenopus laevis skin and eggs were fractionated on sugar-Sepharose columns, to which lactose, melibiose, galactose, rhamnose and mannose had been covalently linked, by successive elution with chelating reagent and specific sugars, resulting in separation of the different Ca2(+)-dependent and Ca2(+)-independent carbohydrate-binding proteins. The skin of X. laevis contains a salt-extractable Ca2(+)-dependent lactose-binding lectin of 30 kilodalton (kDa) and the eggs a similar lectin of 43 kDa, but they both lack Ca2(+)-dependent galactose-binding lectins. The 30 kDa lactose-binding lectin which agglutinates human A erythrocytes was isolated by successive affinity chromatography on two linked sugar-Sepharose columns, i.e., a galactose-Sepharose-lactose-Sepharose (GL) column system. Since the 30 kDa lectin was not recovered in the Ca2(+)-dependent lactose-binding protein fraction from the GL column system under the dithiothreitol (DDT)-free conditions, it was concluded that the lectin requires the presence of DTT and calcium for binding to the lactose-Sepharose column.
Nitta
K
K
Cancer Research Institute, Tohoku College of Pharmaceutical Sciences, Sendai, Japan.
Terasaki
Y
Y
Kusakari
K
K
Onodera
J
J
Kanno
K
K
Kawauchi
H
H
Takayanagi
Y
Y
D000818:Animals; D002352:Carrier Proteins / Q000032:analysis* / Q000302:isolation & purification / Q000378:metabolism; D002846:Chromatography, Affinity; D010063:Ovum / Q000032:analysis*; D011956:Receptors, Cell Surface; D012867:Skin / Q000032:analysis*; D014982:Xenopus laevis / Q000378:metabolism*
D002352:Carrier Proteins; D011956:Receptors, Cell Surface; C055213:saccharide-binding proteins