Dolichol Monophosphate Glucose: An Intermediate in Glucose Transfer in Liver
01 May 1970-Proceedings of the National Academy of Sciences of the United States of America (National Academy of Sciences)-Vol. 66, Iss: 1, pp 153-159
TL;DR: The microsomal fraction of liver has been found to catalyze glucose transfer from UDPG to a lipid acceptor which appears to be identical to the compound obtained by chemical phosphorylation of dolichol.
Abstract: The microsomal fraction of liver has been found to catalyze glucose transfer from UDPG to a lipid acceptor which appears to be identical to the compound obtained by chemical phosphorylation of dolichol. The substance formed (dolichol monophosphate glucose) is acid labile and yields 1,6-anhydroglucosan by alkaline treatment. It can be used as substrate by the enzyme system yielding a glucoprotein which is subsequently hydrolyzed to glucose.
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01 Jan 1984
TL;DR: In this paper, the cellular biology and biochemistry of the retinoids are discussed and the effects of retinoid on cell differentiation in many different types of epithelia.
Abstract: Publisher Summary This chapter discusses the cellular biology and biochemistry of the retinoids In isolated 9-day-old rat embryos, retinoic acid prevents the formation of the pharyngeal arches, which are derived from cephalic mesenchyme; these structures later form the maxilla and the mandible Another mesenchymal derivative, whose formation is markedly suppressed by retinoic acid in rat embryos, is the yolk sac circulation Retinoids can exert a powerful influence on cell differentiation in many different types of epithelia The effects of retinoids on differentiation of epithelia in organ culture result from a combination of complex cellular responses and interactions of different cell types in the explant One of the most illuminating examples of the ability of retinoids to promote differentiation is the effect of retinoids on mouse embryonal carcinoma cells These undifferentiated stem cells of teratocarcinomas are multipotential, that is, they can differentiate into a multiplicity of somatic cell types Another example of the ability of retinoic acid to promote terminal differentiation of neoplastic cells to nonneoplastic cell types is the effect of retinoic acid on human promyelocytic leukemia cells
682 citations
01 Jan 1980
TL;DR: The segregation of the proteoglycans into a separate category is based on a few specific characteristics, including the fact that the d-glucuronic-acid-containing repeating disaccharide of chondroitin, N-acetylchondrosine, has recently been identified as a component of thyroglobulin.
Abstract: With the possible exception of hyaluronic acid, the connective tissue polysaccharides are all synthesized by their parent cells as components of proteoglycans. In these substances, a number of polysaccharide chains are covalently linked to a protein core; e.g., in the proteoglycan of bovine nasal cartilage, which is the prototype of molecules of this kind, close to 100 chondroitin sulfate chains, with a molecular weight of approximately 20,000, and slightly fewer keratan sulfate chains are linked to a core protein (mol. wt. 200,000) which constitutes 7–8% of the entire molecule. In many respects, the proteoglycans are similar to other protein-bound complex carbohydrates, and the conspicuous polysaccharide component per se does not distinguish the proteoglycans from the class of glycoproteins; e.g., there are members of the glycoprotein class, such as the blood group substances, which have a high relative content of carbohydrate consisting of a substantial number of monosaccharide units. Rather, the segregation of the proteoglycans into a separate category is based on a few specific characteristics: (1) each polysaccharide consists of repeating disaccharide units in which a hexosamine, d-glucosamine, or d-galactosamine is always present; (2) all connective tissue polysaccharides except keratan sulfate contain a uronic acid, either d-glucuronic acid or its 5-epimer, l-iduronic acid, or both; (3) ester sulfate groups are present in all members of the group except in hyaluronic acid; in addition, N-sulfate groups are found in heparin and heparan sulfate. Although certain other bipolymers are known to contain ester sulfate, e.g., some epithelial mucins (Horowitz, 1977), these compounds are clearly distinguishable from the connective tissue polysaccharides by the other criteria indicated above. It may also be mentioned that the d-glucuronic-acid-containing repeating disaccharide of chondroitin, N-acetylchondrosine, has recently been identified as a component of thyroglobulin (Spiro, 1977); however, since the disaccharide is present as a single unit, thyroglobulin may not be considered a proteoglycan.
393 citations
TL;DR: The main aspects of the biogenesis of O-linked carbohydrate chains in S. cerevisiae, Candida albicans, and other fungi are discussed and the occurrence of PMT orthologs in higher eukaryotes such as Arabidopsis, Drosophila and mammals is reported and discussed.
295 citations
TL;DR: Many of the severe developmental disturbances in children are related to protein glycosylation, for example, the CDG syndrome and congenital muscular dystrophies with neuronal-cell-migration defects have been elucidated with the help of yeast.
Abstract: Proteins can be modified by a large variety of covalently linked saccharides. The present review concentrates on two types, protein N-glycosylation and protein O-mannosylation, which, with only a few exceptions, are evolutionary conserved from yeast to man. They are also distinguished by some special features: The corresponding glycosylation processes start in the endoplasmatic reticulum, are continued in the Golgi apparatus, and require dolichol-activated precursors for the initial biosynthetic steps. With respect to the molecular biology of both types of protein glycosylation, the pathways and the genetic background of the reactions have most successfully been studied with the genetically easy-to-handle baker's yeast, Saccharomyces cerevisae. Many of the severe developmental disturbances in children are related to protein glycosylation, for example, the CDG syndrome (congenital disorders of glycosylation) as well as congenital muscular dystrophies with neuronal-cell-migration defects have been elucidated with the help of yeast.
270 citations
TL;DR: It is suggested that SRD5A3 is likely to be the long-sought polyprenol reductase and the genetic basis of one of the earliest steps in protein N-linked glycosylation is revealed.
259 citations
Cites background from "Dolichol Monophosphate Glucose: An ..."
...The identification of Dol-P as glycosyl carrier lipids in glycosylation was described 40 years ago (Behrens and Leloir, 1970), but the role of the free lipid, broadly distributed in mammalian cells (Rip et al., 1985), and some of its biosynthetic steps remain elusive....
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...The identification of Dol-P as glycosyl carrier lipids in glycosylation was described 40 years ago (Behrens and Leloir, 1970), but the role of the free lipid, broadly distributed in mammalian cells (Rip et al....
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