Glycoconjugates

Glycoconjugates

1. They are carbohydrates covalently bound to lipids or proteins and participate in cell adhesion and recognition. They are found on the external face of the cell membrane

   • Glycolipids
     • Membrane Lipids + oligosaccharides
     • They provide fluidity and flexibility to the membrane. They lack phosphate and alcohol groups.
       • Gangliosides
         • sialic acid
         • Abundant nerve tissue
         • fatty acid chains
           • palmitic and stearic
       • Cerebrosides
         • Ceramide and sugar joined by glycosidic bond
           • Glycosylcerebrosides
             • Glucose
           • Galactosylcerebrosides
             • Galactose
   • Glycoproteins
     • proteins + oligosaccharides
       • Sugars
         • Linear
           • Synthesis in Golgi. O-Glucosidic Link
             • serine/threonine
         • Branched
           • Synthesis in endoplasmic reticulum N-Glucoside Link
             • Asparagine
     • These can be hormones, enzymes, receptor proteins, antibodies and growth factors
   • Proteoglycans
     • proteins + polysaccharides
     • High molecular weight because it has many sugar chains. It has a central protein that is usually hyaluronic acid to which the sugar chains are attached with binding proteins that vary in sequence and number of GAGs
       • They retain a high amount of water. Up to 95%.
         • Glycosaminoglycans
           • Hyaluronate Dermatan Sulphate Chondroitin sulphate Heparan sulphate Queratan sulphate
           • glucosamine - galactosamine Unbranched Most have sulphate groups