Transport of CMP‐<i>N</i>‐glycoloylneuraminic acid into mouse liver Golgi vesicles

Lepers, Anne; Shaw, Lee; Cacan, René; Schauer, Roland; Montreuil, Jean; Verbert, André

doi:10.1016/0014-5793(89)80731-8

Cited by 30 publications

(17 citation statements)

References 14 publications

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“…The marked arrows indicate the migration positions of the following non-radioactive co-chromatographed reference substances, which were visualized with the orcinol/Fe3 + reagent: (A) CMP-Neu5Gc; (B) CMP-NeuSAc; (C) NeuSGc; (D) Neu5Ac standards. The integration ratio of these two peaks was 1 : 1, Several other zones of radioactivity were also visible, the suggesting that no preferential uptake of either CMP-most notable being a cluster of four peaks migrating 8-glycoside had occurred, in agreement with previously reported 13 cm, two of which coincided with the migration positions results [23].…”

Section: Analysis Of Soluble Intravesicular Radioactivitysupporting

confidence: 91%

“…mg protein-', K, 1.05 f 0.4 pM. mutual inhibition suggests that CMP-NeuSAc and CMPNeuSGc are internalized by the same carrier molecule, as was proposed for the mouse liver Golgi CMP-sialic-acid transporter [23].…”

Section: Uptake Of Cmp-(14cj"eu5ac and Cmp-(14c]ne~5gc By Rut Liver Gmentioning

confidence: 55%

“…Furthermore, the Golgi-associated CMP -sialic-acid translocator in mouse liver exhibits essentially identical kinetic properties towards CMP-NeuSAc and CMP-Neu5Gc [23], even though mouse liver sialic acids consist mainly of NeuSGc. The Golgi CMPsialic-acid translocator from both organisms is thus unlikely to be of importance in regulating the relative amounts of NeuSGc and NeuSAc incorporated into glycoconjugates.…”

Section: Uptake Of Cmp-(14cj"eu5ac and Cmp-(14c]ne~5gc By Rut Liver Gmentioning

confidence: 93%

“…NeuSGc was prepared from porcine submandibular mucin. CMP- [4,5,6,7,8,9-'4C]Neu5Gc was produced by enzymatic hydroxylation of commercially available CMP-[4,5,6,7,8,9-'4C]Neu5Ac using a high-speed supernatant from mouse liver [23].…”

Section: Reagentsmentioning

confidence: 99%

“…The resulting Golgi membrane pellets were stored at -70'C until use. The membrane preparations were characterized by their content of marker enzymes [23].…”

Section: Protein Concentration Preparation Of Golgi Membranes From Ramentioning

confidence: 99%

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A study on the regulation of N‐glycoloylneuraminic acid biosynthesis and utilization in rat and mouse liver

Lepers

Shaw

Schneckenburger

et al. 1990

European Journal of Biochemistry

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The relative contribution of N-glycoloyl-P-D-neuraminic acid (NeuSGc) to total sialic acids expressed in mouse and rat liver glycoconjugates was found to be 95% and 11%, respectively. This considerable difference in sialic acid composition made these two tissues suitable models for a comparative investigation into the regulation of NeuSGc biosynthesis and utilization.An examination of the CMP-glycoside specificity of Golgi-associated sialyltransferases using CMP-N-acetylp-D-neuraminic acid (CMP-NeuSAc) and CMP-NeuSGc revealed no significant tissue-dependent differences. The Golgi membrane CMP -sialic acid transport system from rat liver did, however, exhibit a slightly higher internalisation rate for CMP-NeuSAc, though no preferential affinity for this sugar nucleotide over CMP-NeuSGc was observed.In experiments, where Golgi membrane preparations were incubated with an equimolar mixture of labelled CMP-NeuSAc and CMP-NeuSGc, no significant tissue-dependent differences in [14C]sialic acid composition were observed, either in the luminal soluble sialic acid fraction or in the precipitable sialic acid fraction, results which are consistent with the above observations. From this experiment, evidence was also obtained for the presence of a Golgi-lumen-associated CMP -sialic acid hydrolase which exhibited no apparent specificity for either CMPNeuSAc or CMP-NeuSGc.The specific activity of the CMP-NeuSAc hydroxylase, the enzyme responsible for the biosynthesis of NeuSGc, was found to be 28-fold greater in high-speed supernatants of mouse liver than of rat liver. No hydroxylase activity was detected in the Golgi membrane preparations. It is therefore proposed that the cytoplasmic ratio of CMPNeuSAc and CMP-NeuSGc produced by the hydroxylase, remains largely unmodified after CMP-glycoside uptake into the Golgi apparatus and transfer on to growing glycoconjugate glycan chains. The close relationship between the total sialic acid composition and the sialic acid pattern in the CMP-glycoside pools of the tissues lends considerable weight to this hypothesis.

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Section: Analysis Of Soluble Intravesicular Radioactivitysupporting

confidence: 91%

Section: Uptake Of Cmp-(14cj"eu5ac and Cmp-(14c]ne~5gc By Rut Liver Gmentioning

confidence: 55%

Section: Uptake Of Cmp-(14cj"eu5ac and Cmp-(14c]ne~5gc By Rut Liver Gmentioning

confidence: 93%

Section: Reagentsmentioning

confidence: 99%

“…The resulting Golgi membrane pellets were stored at -70'C until use. The membrane preparations were characterized by their content of marker enzymes [23].…”

Section: Protein Concentration Preparation Of Golgi Membranes From Ramentioning

confidence: 99%

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