EFFECTS OF PRIMER-CONCENTRATION ON URONOSYL-EPIMERIZATION AND SULFATION PATTERNS IN P-HYDROXYPHENYL-O-BETA-D-XYLOPYRANOSIDE-PRIMED GALACTOSAMINOGLYCANS PRODUCED BY SKIN FIBROBLASTS

By supplying skin fibroblasts with different concentrations of the gal actosaminoglycan chain-primer phydroxyphenyl-O-beta-D-xylopyranoside w e have produced and recovered glycan-chains that were subsequently rad io-iodinated in the hydroxyphenyl group and subjected to sequence anal ysis by using graded enzymic treatment followed by a combination of ge l chromatography and electrophoresis. Fragments extending from the tag ged reducing end to the cleavage-point were identified and quantified. Degradation by chondroitin B lyase of chains primed at 0.1 or 0.5 mM xyloside gave profiles indicating a periodic and wave-like distributio n of iduronate-containing repeats, with high incidence around position s 2, 5 and onwards, whereas in chains produced at 1.0 mu xyloside the incidence of iduronate was similar in positions 1-4 and then declined. Degradation by chondroitin AC lyase indicated a high incidence of glu curonate in or near the linkage-region. There was a relatively uniform degree of sulfation in chains primed at low xyloside concentration, w hereas chains primed at 1.0 mM xyloside gave very heterogeneous charge -patterns in all segments of the chain, including the linkage-region, giving the impression that adequate sulfation, probably at C-4 and at the first opportunity, is necessary to obtain an ordered and periodic epimerization pattern.