Extracellular matrix = macromolecules between cells

Extracellular matrix = macromolecules between cells

1. made of ground substance and fibers

   • ground substance = GAGs/proteoglycans (mostly carbohydrates)
     • carbohydrates
       • one of 4 classes of biomolecules
       • functions
         • major fuel source
         • major structural role
         • components of other biomolecules
         • cell surface interactions (signaling, adhesion)
         • biofilms (ex: dental plaque - plaque polly saccharides store fuel and attachment site for bacteria)
       • common empirical formula: (CH2O)n, n>=3
       • suffix: -ose, prefix: glyco-
       • monosaccharides = simple sugards
         • several OH groups
         • very hydrophilic
         • most comon: hexoses (6Cs)
           • ex: glucose
       • oligosaccharides/polysaccharides
         • monosaccharide units linked by glycosidic bond
   • fibers = fibrous proteins, structure and/or adhesive
   • types of macromolecules
     • glycosaminoglycans (GAG) aka mucopolysaccarides
       • 100% CHO
       • structure: repeating disaccharide (AB)n
         • A = uronic acid (C5 as COO-)
         • B = glycosamine (amino sugar) derivative
       • exists in 3 forms
         • independent molecules (not covalently linked to other molecules): hyaluronate, heparin
         • larger structure: proteoglycan
       • unbranched polymer
         • glycosidic linkage
         • C1 usually linked to hydroxy of adjacent unit usually ß1,4 or ß1,3
     • proteoglycans aka mucoproteins
       • 90-95% CHO
     • glycoproteins
       • 2-80% CHO
     • fibrous proteins
       • 1-2% CHO

2. abundant in connective tissues vs. many tissues are cellular

3. functions

   • mechanical support
   • cushioning
   • lubrication
   • adhesives
   • selective filtering
   • cell sapces

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