Ous acid at pH 3 for DS heparin, and 6-O-DS heparin by CD33 Proteins Molecular Weight partial depolymerization with nitrous acid at pH 3 for ten min., ten where where two,5-anhydromannitol residues, abbreviated as AManR , were generated at decreasing ends min., 2,5-anhydromannitol residues, abbreviated as AManR, were generated at minimizing ends (Figure 2) 2) [58]. The resultingoligosaccharides were separated according toto size by gel-filtration, and (Figure [58]. The resulting oligosaccharides were separated according size by gel-filtration, after which additional fractionated by ion-exchange chromatography to separate them determined by on their charges. then further fractionated by ion-exchange chromatography to separate them primarily based their charges. The obtained 6-mers, 8-mers, 10-mers, and 12-mers had been enriched inin IdoA (2-O-S) lcNS (6-O-S), The obtained 6-mers, 8-mers, 10-mers, and 12-mers have been enriched IdoA (2-O-S) lcNS (6-O-S), IdoA lcNS (6-O-S), and IdoA (2-O-S) lcNS disaccharide sequences (80). These oligosaccharides IdoA lcNS (6-O-S), and IdoA (2-O-S) lcNS disaccharide sequences (80). These oligosaccharides were their binding for their to FGFs and their ability to market biological activity had been then evaluated for then evaluatedaffinities binding affinities to FGFs and their capability to market biological activity (Figure 2) [16,58]. (Figure two) [16,58].FGFFigure two. 2. Trk receptors Proteins site Preparation of size- and structure-defined oligosaccharides from native, 2-O-desulfation Preparation of size- and structure-defined oligosaccharides from native, 2-O-desulfation (DS) Figure and 6-O-DS6-O-DS heparins. (DS) and heparins.Oligosaccharides derived from chemically modified heparins bind to to each FGF-1 and FGF-2, Oligosaccharides derived from chemically modified heparins bind each FGF-1 and FGF-2, with various affinities. Our structural studies applying selectively modified 2-O- and 6-O-DS heparins with different affinities. Our structural research employing selectively modified 2-O- and 6-O-DS heparins suggested that the structural requirements for heparin and HS to to bind to FGF-1 are diverse from suggested that the structural specifications for heparin and HS bind to FGF-1 are different from these forthose for to FGF-2 to FGF-2 [20,58,59]. One example is, the chlorate-treated A31not create endogenous binding binding [20,58,59]. One example is, the chlorate-treated A31 cells do cells do not make sulfated heparan sulfate heparan sulfate proteoglycan (HSPG) and intact heparin can restore the of endogenous sulfated proteoglycan (HSPG) and intact heparin can restore the mitogenic activities both FGF-1 and FGF-2 in these cells. The partial 2-O-DS of heparin decreases theheparin to restore the mitogenic activities of each FGF-1 and FGF-2 in these cells. The partial 2-O-DS of capability decreases mitogenic activities of both FGF-1 and FGF-2, and 75 or higher 2-O-DS entirely abolishes this capability [49]. Similarly, partial 6-O-DS of heparin decreases the capability to restore the mitogenic activity of FGF-1, and 62.two or higher 6-O-DS outcomes within the full loss of mitogenic ability [51]. In contrast, partial 6-O-DS as much as 66.8 substantially decreased the ability to restore FGF-2 activity. Thus, a highMolecules 2019, 24,six ofcontent of 6-O-sulfate groups in heparin/HS, as well as a higher content of 2-O-sulfate and N-sulfate, is required for the activation of FGF-1, but not for FGF-2 [49,51]. Selectively O-desulfated heparin was applied to affinity column-immobilized FGF-1 or FGF-2 and eluted while using a discontin.