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- Appelkvist, Eeva-Liisa, 1945-
(författare)
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Glycosylation of microsomal proteins and their relationship to peroxisomes
- 1982
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The distribution of glycoproteins in rough and smooth microsomes and Golgi membranes was studied using proteolytic treatment of intact vesicles. About half of the protein-bound sugar residues could be removed by this treatment, indicating the presence of glycoproteins on both surfaces of the membrane. The properties and distribution of UDP-galactosyl transferase using endogenous proteins as acceptor were analyzed. Dolichol phosphate does not accept galactose and obviously does not participate in this transferase system. The activity is present mainly in Golgi, but also in microsomal membranes and may function in the galactosylation of different proteins in these two organelles. Microsomes, lysosomes, plasma and outer mitochondrial membranes contain dolichol mono- and pyrophosphatases which appear to play an important role in regulation of the level of dolichol phosphate and, thereby, the extent of glycosylation.Peroxisomes can be isolated by the use of glutaraldehyde as a cross-linking reagent and a vertical rotor for centrifugation. These peroxisomes contain enzymes for the g-oxidation of fatty acids as soluble proteins in the luminal compartment and it appears that the fatty acyl carrier protein present in the peroxisomal membrane is responsible for the transport of substrate from the cytoplasm to the vesicle lumen. Precursors of several peroxisomal membrane proteins appear first on the cytoplasmic surface of the ER and are subsequently transported to the peroxisomes.
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