Neoglycoenzymes: a versatile tool for lectin detection in solid-phase assays and glycohistochemistry.
Carbodiimide-mediated coupling of p-aminophenyl glycosides to a naturally nonglycosylated enzyme yields a neoglycoenzyme. This compound combines inherent enzymatic activity with synthetically conferred ligand properties to lectins. Appropriate choice of the ligand allows custom-made synthesis to reliably detect various types of lectins. To exemplify practical applications of this class of compounds, glycosylated bacterial beta-galactosidase has been employed to quantitate plant lectins, immobilized on plastic surfaces as well as on nitrocellulose. Competitive inhibition by specific sugar ascertained the dependence of binding on protein--carbohydrate interactions. In view of lectins as tools, a sandwich lectin-binding assay for high mannose-type glycoprotein detection has been modified to principally facilitate wide application to other lectin-reactive sugar chains by introducing the neoglycoenzyme. In addition to lectin determination in solid-phase assays, neoglycoenzymes allow one to glycohistochemically localize endogenous lectins in tissue prints and tissue sections with a minimum number of steps. This nonradioactive, rapid, sensitive, and convenient assay concept, based on conjugation of a ligand to an enzyme with maintenance of its receptor-binding activity, may find extended application beyond lectinology in receptor analysis.
Gabius
S
S
Medizinische Universitätsklinik, Abteilung Hämatologie-Onkologie, Göttingen, Federal Republic of Germany.
Hellmann
K P
KP
Hellmann
T
T
Brinck
U
U
Gabius
H J
HJ
D001710:Biotin / Q000378:metabolism; D002234:Carbodiimides / Q000378:metabolism; D050260:Carbohydrate Metabolism; D005696:Galactosidases / Q000378:metabolism*; D006001:Glycoconjugates / Q000096:biosynthesis*; D006023:Glycoproteins / Q000378:metabolism; D006031:Glycosylation; D006651:Histocytochemistry / Q000379:methods; D037102:Lectins / Q000032:analysis; D001616:beta-Galactosidase / Q000378:metabolism*
D002234:Carbodiimides; D006001:Glycoconjugates; D006023:Glycoproteins; D037102:Lectins; D001710:Biotin; D005696:Galactosidases; D001616:beta-Galactosidase