Soluble and membrane lectin-binding glycoproteins of the chromaffin granule
Cahill, A.L.; Morris, S.J.
Journal of Neurochemistry 32(3): 855-867
1979
ISSN/ISBN: 0022-3042 PMID: 430065 Accession: 006436240
Fluorescein isothiocyanate-labeled lectins were used to identify lectin-binding glycoproteins of the chromaffin granule of the chick after electrophoresis of the membrane and soluble granule proteins on sodium dodecyl sulphate polyacrylamide slab gels. The glycoprotein nature of all lectin-binding bands was confirmed by staining the gels for carbohydrates, and the specificity of the lectin-binding was demonstrated by hapten sugar inhibition of binding. In samples of granule membrane proteins reduced with dithiothreitol 10 concanavalin A (Con A), 5 wheat germ agglutinin, 8 Ricinus communis agglutinin-60, and 7 R. communis agglutinin-120 (RCA-120) binding glycoproteins were identified. MW of these glycoproteins varied from 20,000 to 200,000 daltons. All but 2 of the Con A-binding bands and 1 of the RCA-120 binding bands appeared to react with > 1 lectin, suggesting possible carbohydrate heterogeneity in these membrane glycoproteins. The band identified as dopamine .beta.-hydroxylase reacted most intensely with all 4 lectin tested, and in the soluble core material this enzyme was the sole significant lectin binding glycoprotein.