Influence of glycopeptide structure on the regulation of galactosyltransferase activity

Ak, Rao; Mendicino, Joseph

doi:10.1021/bi00619a008

Cited by 33 publications

(27 citation statements)

References 22 publications

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“…Human IgG possesses an asparagine-linked oligosaccharide in the heavy-chain domain (49), and carbohydrates are linked to the same domain of pig IgG (34). Depletion of carbohydrates in pig IgG was performed and had no effect on the capacity of the 52-kDa protein to bind to it.…”

Section: Discussionmentioning

confidence: 99%

Purification and characterization of a 52-kilodalton immunoglobulin G-binding protein from Streptococcus suis capsular type 2

et al. 1995

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Section: Discussionmentioning

confidence: 99%

Purification and characterization of a 52-kilodalton immunoglobulin G-binding protein from Streptococcus suis capsular type 2

et al. 1995

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“…Both cell lines show a decrease in activities of GlcNAc transferase and galactose transferase, while NeuNAc transferase remains at nearly normal levels. Recently, Rao et al [27] have shown that sialylation of a terminal galactose residue present on one arm of a branched oligosaccharide severely restricts addition of galactose to the second arm of the structure. It could be argued, therefore, that in RicR15 and RicR21 cells the addition of galactose (and N-acetylglucosamine) becomes rate-limiting and any galactose added to a nascent chain containing a terminal N-acetylglucosamine (see for example immunoglobulin glycopeptide B, Fig.…”

Section: Discussionmentioning

confidence: 99%

“…An homogenous galactosyl transferase preparation catalysed the addition of galactose to one terminus of a branched N-glycan but the product of this reaction was a poor substrate for the addition of a second terminal galactose [27], suggesting that in vivo there may be more than a single GalPl+4GlcNAc-synthesising galactosyl transferase.…”

Section: Galactosyl Transferasementioning

confidence: 99%

Glycosyl Transferases of Baby‐Hamster‐Kidney (BHK) Cells and Ricin‐Resistant Mutants

Vischer

Hughes

1981

European Journal of Biochemistry

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Five cell lines of ricin-resistant BHK cells have been assayed for gross carbohydrate analysis of cellular glycoproteins, for the activities of several glycosidases and of specific glycosyl transferases active in assembly of N-glycans of glycoproteins. The latter enzymes include sialyl transferase using asialofetuin as glycosyl acceptor, fucosyl transferases using asialofetuin and asialoagalactofetuin acceptors, galactosyl transferases using ovalbumin, ovomucoid and N-acetylglucosamine as acceptors and N-acetylglucosaminyl transferases using ovalbumin and glycopeptides as acceptors.Cell line Ric'14, binding less ricin than normal BHK cells, contains reduced amounts of sialic acid, galactose and N-acetylglucosamine in cellular glycoproteins and lacks almost completely N-acetylglucosamine transferase I, an essential enzyme in assembly of ricin-binding carbohydrate sequences of N-glycans. These cells also contain reduced levels of N-acetylglucosamine transferase I1 active on a product of N-acetylglucosamine transferase I action. Sialyl transferase activity is severely depressed while fucose-(a1 -+ 6)-N-acetylglucosamine fucosyl transferase activity is increased. Cell lines RicR15, 17, 19 and 21 showed partial deficiencies in galactosyl and N-acetylglucosaminyl transferases. A hypothesis is put forward to account for the different carbohydrate compositions and ricin binding properties of glycoproteins synthesised by these cells in terms of the determined enzyme defects, the normal level of sialyl transferases detected in Ric'15 and Ric'21 cells and the elevated levels of sialyl and fucosyl transferases detected in RicR17 and 19 cells.None of the above changes in glycosyl transfer reactions in the RicR cell lines are due to enhanced glycosidase or sugar nucleotidase activities in the mutant cells.Several laboratories have isolated over the last five years cell lines resistant to the high cytotoxicity of the plant lectin, ricin [l-101. In our own work [1,2] 22 cell lines of baby hamster kidney (BHK) fibroblasts were described and classified into four main phenotypic classes on the basis of the degree of cross-resistance to two other toxic lectins, Phaseolus vulgaris phytohaemagglutinin and concanavalin A shown by each cell line and by their ability to bind ricin and the other two lectins. One phenotypic class appeared to be qualitatively similar to ricin-resistant cell lines of Chinese hamster ovary (CHO) cells isolated by others [3-61. Cell lines of this class were highly resistant, compared with the parental cells, to P. vulgaris phytohaemagglutinin as well as to ricin, were more sensitive to concanavalin A cytotoxicity and bound as little as 10 % or less of the ricin bound by parental cells. Ricin binds to cellsurface oligosaccharides containing terminal galactose or Abbreviutions. BHK cells, baby hamster kidney cell line; CHO cells, Chinese hamster ovary cell line; GlcNAc, N-acetylglucosamine; NeuNAc, N-acetylneuraminic acid; NaCI/Pi, phosphate-buffered saline;

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“…A comparable enzyme is also isolated from fetal calf serum [25] and from rat liver (Km 10.8 /~M) and serum (Kin 12.5 t~M); both Km values were determined with asialo-agalacto-fetuin [19]. The molecular structure of the acceptor can significantly influence the apparent Km for UDPgalactose [26]. Berger et al have found a high specificity for the human serum enzyme that catalyzes only Galfl(1--4)GlcNAc bond formation [27].…”

Section: Discussionmentioning

confidence: 99%

Role of galactosyl-transferases in rat gastric epithelial glycoprotein synthesis

Strous

Hendriks

Kramer

1980

Biochimica et Biophysica Acta (BBA) - Enzymology

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Influence of glycopeptide structure on the regulation of galactosyltransferase activity

Cited by 33 publications

References 22 publications

Purification and characterization of a 52-kilodalton immunoglobulin G-binding protein from Streptococcus suis capsular type 2

Purification and characterization of a 52-kilodalton immunoglobulin G-binding protein from Streptococcus suis capsular type 2

Glycosyl Transferases of Baby‐Hamster‐Kidney (BHK) Cells and Ricin‐Resistant Mutants

Role of galactosyl-transferases in rat gastric epithelial glycoprotein synthesis

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