Alkaline borohydride treatment

Carlson (6) had shown earlier that porcine submaxillary glycoproteins (PSM) produced five reduced oligosaccharides after alkaline borohydride treatment (conditions 0.05M KOH, M NaBH4 at 45°C for 15 hours) removal of more than 90% of the side chains was reported. The oligosaccharides were separated and varied in size from mono to pentasaccharides. Katzman and Eylar (50) found similar but not identical oligosaccharides to be present in PSM, prepared by a different method. 

Changes in Amino Acid Composition Following Alkaline Borohydride Treatment of the Glycopeptide... 

The 0-glycosically linked carbohydrate chains of fetuin have been cleaved from the protein by alkaline borohydride treatment. Structural analysis revealed the existence of tri- and tetra-saccharides linked 0-glycosidically to L-serine or L-threonine and having structures identical to those previously identified for bovine K-casein and human chorionic gonadotrophin [(27) and (28)]. The A-glycosidically linked chains of fetuin have been assigned structures (36) %r (37). ... 

Two sulphated oligosaccharides have been isolated from ovomucin by alkaline borohydride treatment of glycopeptides. The structure (65) of one of these components has been reported. ... 

Fig. 5. Proposed structures for reduced oligosaccharides isolated from blood group A-positive porcine submaxillary mucin by alkaline borohydride treatment (from Carlson, 1968). Three reduced oligosaccharides are shown in the figure and three others were obtained which are not illustrated above but which were identical to oligosaccharides I, II, and III, respectively, except for the absence of the sialyl residue. Ac, acetyl Gly, glycolyL...

The effect of a reducing sodium borohydride treatment followed by a mildly alkaline wash on the physical properties and stability of paper was studied. Test papers were characterized by measuring their initial pH value, brightness, and folding endurance. Then they were subjected to borohydride treatment and washed with dilute calcium hydroxide solution or deionized water. The concentrations of sodium borohydride... 

A shorter but less selective route to la-hydroxycholesterol has been described by Kaneko (90). Cholesta-l,4-dien-3-one (90) was deconjugated to its -isomer and then reduced with borohydride to give 3P-hydroxy-cholesta-1,5-diene (91). Selective hydroboration followed by alkaline peroxide treatment afforded a 30% yield of a separable 1 1 mixture of la- and 2a-hydroxycholesterol (89) and (93). If the acetate (92) was hydrated by an oxymercuration-demercuration procedure, a mixture of the 2 3-hydroxycholesterol (94) (14%) and la-hydroxycholesterol (89) (26%) was isolated after saponification (118). When starting with the readily available cholesta-l,4,6-trien-3-one, the deconjugation and reduction afforded 3P-hydroxycholesta-l,5,7-triene (95) (59). The 5,7-diene system was then protected as its 4-phenyl-l,2,4-triazoline-3,5-dione (PTD) adduct (96). Treatment of (96) with m-chloroperbenzoic acid gave a 5 3 mixture of the lp,2p- and la,2a-epoxides (98). More recently, Whalley and his co-workers have found that if the dimethyl-t-... 

Two oligosaccharide side-chains (48, 49) have been isolated from apolipo-protein C-III of human plasma low density lipoprotein by treatment with alkaline borohydride. ... 

The structures of three new disialylfucosyl hexasaccharides, two new nona-saccharides, and a pentasaccharide isolated from human milk have been elucidated. The structures indicate that, in contrast to those of the ABO and Lewis blood-groups, the H determinant is located only on the type-I carbohydrate chain of the branched moiety. Extraction of bovine milk-fat globule membranes with phenol afforded three glycoproteins, which released the T antigen on treatment with alkaline borohydride and desialylation. ... 

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