Glyco-site

Here we have demonstrated that nature of the oligosaccharide product and the glyco-sidic linkage specificity of glucansucrases can be modified by site-directed/random... 

Goodson, R.J., and Katre, N.V. (1990) Site-directed pegylation of recombinant interleukin-2 at its glyco-sylation site. Bio/Technology 8, 343-346. 

Liu, X., Davis, D., and Segaloff, D. L. (1993) Disruption of potential sites for N-hnked glyco-sylation does not impair hormone binding to the lutropin/choriogonadotropin receptor if Asn-173 is left intact. J. Biol. Chem. 268, 1513-1516. 

Ipomoea operculata has afforded three resin glycosides containing this glyco-sidic acid, operculins VI (19), XI (20), and XII (21). The macrolactone site was located at C-2 of the first rhamnose unit for 19 while in compounds 20 and 21 the lactonization was placed at C-3, the same site for mammosides A (17) and B (18). Two dodecanoyl residues are the fatty acids present in these resin glycosides and located at C-2 of the second rhamnose and at C-4 of the third rhamnose for operculin VI (19). For operculins XI (20) and XII (21), they were placed at C-2 or C-3 of the second rhamnose and C-4 at the third rhamnose (27). 

Collins A, Lonjou C, Morton NE (1999) Genetic epidemiology of single-nucleotide polymorphisms [see comments]. Proc Natl Acad Sci U S A 96 15173-15177 Cordon-Cardo C, O Brien JP, Casals D, et al (1989) Multidrug-resistance gene (P-glyco-protein) is expressed by endothelial cells at blood-brain barrier sites. Proc Natl Acad Sci US A86 695-698... 

All proteins and peptides display chemical and physical instability that affects the way they are distributed and cleared in the body and their delivery to the site of action. Physical and chemical instability is affected by primary sequences and secondary and tertiary structures and the degree of glyco-sylation of protein. Chemical degradation of proteins and peptides involves deamidation, racemization, hydrolysis, oxidation, beta elimination, and disulfide exchange. Physical degradation of proteins involves denaturation and aggregation. 

Apart from hemoglobin, various other proteins have been shown to be glycosylated by one of the methods described above. With the exception of insulin and albumin, however, the specific glyco-sylation sites remain to be elucidated. 

Shapiro AB, Ling V. Positively cooperative sites for drug transport by P-glyco-protein with distinct drug specificities. Eur J Biochem 1997 250(1) 130-137. 

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