Identity of macromolecules present in the extracellular slime layer of Staphylococcus epidermidis

The extracellular slime layer of Staphylococcus epidermidis ATCC 35983 contains: a) two non-anionic carbohydrate containing proteins degradable with papain of molecular masses 250 and 125 kDa; b) a polydisperse but homogeneously-charged acidic population with M r, ranging from 120 000 to 35 000 (average M r 80 000) containing a polysaccharide covalently bound to a small peptide; c) a papain degradable macromolecule (molecular mass 60 kDa) bearing acidic carbohydrates covalently bound to protein; and c) two acidic polysaccharides strongly retained by the anion-exchange column; one polyssacharide is sulphated and has a molecular mass of 20 kDa; the other has a higher charge density and a molecular mass of 12.5 kDa. The results obtained clearly demonstrate the presence of discrete macromolecules in the extracellular material of slime-producing S epidermidis, the majority of which contain acidic carbohydrates, whose biological role remains to be elucidated.