Biosynthesis of arabinogalactan-protein in Lolium multiflorum (Italian ryegrass) endosperm cells. Subcellular distribution of galactosyltransferases.
Intracellular membranes from protoplasts of Italian-ryegrass (Lolium multiflorum) endosperm cells have been fractionated on sucrose density gradients and identified on the basis of putative-marker-enzyme assays. Galactosyltransferases capable of incorporating galactose from UDP galactose into 66% ethanol-soluble products are associated with all membrane fractions. Affinity chromatography of the ethanol-insoluble products on (murine myeloma protein J539)-Sepharose reveals that the enzymes responsible for the synthesis of polymers containing (1----6)-beta-D-galactose residues are associated exclusively with subcellular fractions enriched in Golgi-derived membranes. This suggests that the Golgi apparatus plays an important part in the synthesis of the carbohydrate component of the ryegrass arabinogalactan-protein.
D002499:Centrifugation, Density Gradient; D005700:Galactosyltransferases / Q000378:metabolism*; D007425:Intracellular Membranes / Q000201:enzymology; D008274:Magnesium / Q000378:metabolism; D009088:Mucoproteins / Q000096:biosynthesis*; D010940:Plant Proteins; D006109:Poaceae / Q000378:metabolism; D012639:Seeds / Q000378:metabolism*; D013347:Subcellular Fractions / Q000201:enzymology
D009088:Mucoproteins; D010940:Plant Proteins; C006619:arabinogalactan proteins; D005700:Galactosyltransferases; D008274:Magnesium