P-Galactosylation

A quite different situation holds for collagen in which P-galactosyl units and glucosyl-P-galactosyl disaccharide units are attached to side chains of hydroxy-lysine formed by postsynthetic modification of the original procollagen chain. 

Figure 3 Posttranslational modifications in collagen, (a) 3(S)-hydroxyproline. (b) 4(R)-hydroxyproline. (c) 5-hydroxylysine. (d) O-p-galactosyl-5-hydroxylysine. (e) 2-0-a-D-glucosyl-0-p-D-galactosyl-5-hydroxylysine.

Johnston, D.S., Wright, W.W., Shaper, J.H., Hokke, C.H., van den Eijnden, D.H., and Joziasse, D.H. (1998). Murine sperm-zona binding, a fucosyl residue is required for a high affinity sperm-binding ligand. A second site on sperm binds a nonfucosylated, P galactosyl-capped oligosaeeharide. J. Biol. Chem. 275 1888-1895. 

Although the E461G mutant undergoes the normal sort of acid-base mutant catalytic rescue with nucleophiles, giving p-galactosyl azide, acetate and butyrate in the presence of azide, acetate and butyrate anions, the smaller formate ion, when bound in the hole left by truncation of residue 461 from CH2-CH2-COO- to H, acts as a general base, rather than a nucleophile and accelerates production of (3-galactopyranose. ... 

Chagasic sera did not differentiate between glycolipids with terminal p glucosyl or p galactosyl non-reducing units. They however discriminated between glucosylceramides with differences in the ceramide structure. These results suggest that antibody... 

Sphingomyelinase Ceramidase P-Glucocerebrosidase P-Galactosyl hydrolase P-Hexosaminidase A P-Galactosidase a-Galactosidase P-Hexosaminidases A and B Galactocerebrosidase Arylsulfatase A... 

D-Lactitol (4-0-(p- galactosyl)-D-glucitol) is an interesting and expensive (10 g 300) glycoside made of a cyclic galactopyranose and an open-chain glu-citol. It is obtained by reduction of lactose with sodium borohydride or, technically, by catalytic hydrogenation. It is useful as sweetener for diabetics and does not induce dental caries. 

Various cerebrosides to have been reported are the P-D-glucopyranosyl compound which is the major component of Penicillium cerebrosides, an a-galactosylated cerebroside, the ceramide asymmetric parts of which were made from lyxose, which is described in Chapter 24, and the P-galactosyl compound 22 which shows anti-viral activity. ... 

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