S-Adenosylmethionine in the Vacuole of Candida Utilis

Svihla, G.; Schlenk, F.

doi:10.1128/jb.79.6.841-848.1960

Cited by 57 publications

(28 citation statements)

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“…From this pool methyl groups are transferred by specific methyltransferases on to their physiological acceptors.Since the early experiments of Stekol et al (1958), who observed an increased formation of methylated products by rat liver slices in the presence of exogenous SAM, various groups have looked for a specific uptake system for SAM. This would offer the opportunity to label the internal SAM pool directly and allow measurements of transfer of methyl groups on to proteins without interference Abbreviations used: Hepes, 4-(2-hydroxyethyl)l-piperazine-ethanesulphonic acid; PtdEtn, phosphatidylmonoethanolamine; Ptd[EtnI2, phosphatidyldiethanolamine; PtdCho, phosphatidylcholine; SAM, S-adenosyl-L-methionine; SDS, sodium dodecyl sulphate.be incorporated into plasma-membrane with the incorporation of labelled methionine via protein synthesis.An uptake system for SAM has indeed been described for yeast cells by Svihla & Schlenk (1960) and by Spence (1971) and was characterized by Murphy & Spence (1972). The transport was temperature-and energy-dependent, had an apparent Km for SAM of 3.3,pM and was inhibited by S-adenosylhomocysteine and S-adenosylethionine.…”

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Methyl group transfer from exogenous S-adenosylmethionine on to plasma-membrane phospholipids without cellular uptake in isolated hepatocytes

Phi¹,

Söling²

1982

Biochemical Journal

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At external concentrations of 50,UM, L-methionine was rapidly taken up by hepatocytes, whereas almost no S-adenosylmethionine (SAM) was removed from the incubation medium. SAM did not enter the intracellular water space but equilibrated with a very small pool, which was most likely to be situated on the external side of the plasma membrane. Methyl groups from external L-methionine, but not from external SAM, were incorporated into total and nuclear RNA. A significant incorporation of methyl groups into phospholipids occurred not only with methionine but also with SAM. After subfractionation of hepatocytes it became evident that methyl groups from SAM were mainly incorporated into plasma-membrane phospholipids, and that phospholipid methylation in other cellular compartments resulted from contamination with plasma membrane. The pattern of methylation of the various phospholipid species with SAM as precursor was different from that obtained with L-methionine. In contrast with external L-methionine, external SAM did not enter the intracellular SAM pool. According to these results a transport system for SAM does not exist in rat hepatocytes, although methyl groups from external SAM can phospholipids from the outside.Studies concerning transmethylation processes in intact cells or tissues can be done by using [Me-3H]or [Me-14C1-methionine. After entering the cell the labelled methionine is converted into the corresponding labelled SAM, which then mixes with the internal pool of unlabelled SAM. From this pool methyl groups are transferred by specific methyltransferases on to their physiological acceptors.Since the early experiments of Stekol et al. (1958), who observed an increased formation of methylated products by rat liver slices in the presence of exogenous SAM, various groups have looked for a specific uptake system for SAM. This would offer the opportunity to label the internal SAM pool directly and allow measurements of transfer of methyl groups on to proteins without interference Abbreviations used: Hepes, 4-(2-hydroxyethyl)l-piperazine-ethanesulphonic acid; PtdEtn, phosphatidylmonoethanolamine; Ptd[EtnI2, phosphatidyldiethanolamine; PtdCho, phosphatidylcholine; SAM, S-adenosyl-L-methionine; SDS, sodium dodecyl sulphate.be incorporated into plasma-membrane with the incorporation of labelled methionine via protein synthesis.An uptake system for SAM has indeed been described for yeast cells by Svihla & Schlenk (1960) and by Spence (1971) and was characterized by Murphy & Spence (1972). The transport was temperature-and energy-dependent, had an apparent Km for SAM of 3.3,pM and was inhibited by S-adenosylhomocysteine and S-adenosylethionine. Similar findings were obtained by Nakamura & Schlenk (1974). Stramentinoli et al. (1978a,b) found a transport system for SAM in rabbit erythrocytes. Zappia et al. (1978) described the transport of exogenous SAM into isolated perfused rat livers, and Stramentinoli et al. (1978) claimed even that exogenous SAM was able to protect rat livers against galactosamineinduced liver...

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confidence: 90%

“…An uptake system for SAM has indeed been described for yeast cells by Svihla & Schlenk (1960) and by Spence (1971) and was characterized by Murphy & Spence (1972). The transport was temperature-and energy-dependent, had an apparent Km for SAM of 3.3,pM and was inhibited by S-adenosylhomocysteine and S-adenosylethionine.…”

mentioning

confidence: 96%

Methyl group transfer from exogenous S-adenosylmethionine on to plasma-membrane phospholipids without cellular uptake in isolated hepatocytes

Phi¹,

Söling²

1982

Biochemical Journal

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“…It is insensitive to azide and 2,4-dinitrophenol which strongly inhibit the glucose-dependent accumulation of Sadenosyl-L-methionine in spheroplasts. 4. The transport of S-adenosyl-L-methionine into vacuoles ic optimal at pH 7.4 and is insensitive to nystatin while the uptake of S-adenosyl-L-methionine into spheroplasts is optimal at pH 5.0 and is strongly sensitive to nystatin.…”

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The Transport of S-Adenosyl-l-methionine in Isolated Yeast Vacuoles and Spheroplasts

Schwencke

Robichon-Szulmajstfr

1976

Eur J Biochem

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1. The properties of S-adenosyl-L-methionine accumulating system for both vacuoles and spheroplasts are described. Yeast vacuoles were obtained by a modified metabolic lysis procedure from spheroplasts of Saccharomyces cerevisiae.2. Isolated vacuoles accumulate S-adenosyl-L-methionine by means of a highly specific transport system as indicated by competition experiments with structural analogs of S-adenosyl-L-methionine. The S-adenosyl-L-methionine transport system shows saturation kinetics with an apparent K , of 68 pM in vacuoles and 11 pM in spheroplasts.3. S-Adenosyl-L-methionine accumulation into vacuoles does not require glucose, phosphoenolpyruvic acid, ATP, ADP nor any other tri-or di-phosphorylated nucleotides. It is insensitive to azide and 2,4-dinitrophenol which strongly inhibit the glucose-dependent accumulation of Sadenosyl-L-methionine in spheroplasts.4. The transport of S-adenosyl-L-methionine into vacuoles ic optimal at pH 7.4 and is insensitive to nystatin while the uptake of S-adenosyl-L-methionine into spheroplasts is optimal at pH 5.0 and is strongly sensitive to nystatin. On this basis it has thus been possible to measure both the intracytoplasmic and the intravacuolar pool of S-adenosyl-L-methionine.5. Our results indicate the existence of a highly specific S-adenosyl-L-methionine transport system in the vacuolar membrane which is clearly different from the one present in the plasma membrane of yeast cells.

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“…The convincing demonstrations by Svihla and co-workers (26)(27)(28) that the ultraviolet microscope can be of considerable use in locating and following the fate of ultraviolet-absorbing substances in living cells provided impetus for the present study. The ability to measure ribonucleoprotein in the chromatoid bodies of living cells has enabled us to draw a much more precise picture of the changes in the concentration of RNA in the cells than has hitherto been possible.…”

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confidence: 80%

LOCALIZATION OF CYTOPLASMIC NUCLEIC ACID DURING GROWTH AND ENCYSTMENT OF ENTAMOEBA INVADENS

Barker

Svihla

1964

The Journal of Cell Biology

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With a modified color-translating ultraviolet microscope, the distribution of material showing an absorption maximum at 265 m~t was studied in samples from whole cultures of Entamoeba invadens at intervals during growth and from cysts allowed to mature under controlled conditions. Absorption by the cytoplasm in general gradually increased as trophozoites approached the period of maximum encystment. In late trophozoites and precystic forms, the absorbing material was concentrated into small bodies which coalesced to form large crystalloids of very high specific absorption. Maximum crystallization occurred in early cysts, where cytochcmical tests have shown the large crystalloids to be ribonucleoprotein. Electron micrographs show that the crystalloids are composed of particles 200 to 300 A in diameter. During cyst maturation the amount of absorbing material per cyst is not visibly reduced, but the large bodies fragment into smaller units until finally there is only a very high diffuse absorption over the entire cyst. From these and other results the hypothesis is advanced that the large crystalloids ("chromatoid bodies") are a manifestation of a special parasite-host adaptive mechanism; ribonucleoprotein is synthesized under favorable conditions, crystallized in the resistant cyst stage, and dispersed in the newly excysted amebae thereby enabling them to establish themselves in a new host by a period of quick growth.

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S-Adenosylmethionine in the Vacuole of Candida Utilis

Abstract: Recently, it has been demonstrated by ultraviolet microscopy that S-adenosylmethionine is accumulated in the vacuole of Candida utilis (Svihla and Schlenk, 1959). The exceptional 1 Research performed under the auspices of the U. S. Atomic Energy Commission.

Cited by 57 publications

References 9 publications

Methyl group transfer from exogenous S-adenosylmethionine on to plasma-membrane phospholipids without cellular uptake in isolated hepatocytes

Methyl group transfer from exogenous S-adenosylmethionine on to plasma-membrane phospholipids without cellular uptake in isolated hepatocytes

The Transport of S-Adenosyl-l-methionine in Isolated Yeast Vacuoles and Spheroplasts

LOCALIZATION OF CYTOPLASMIC NUCLEIC ACID DURING GROWTH AND ENCYSTMENT OF ENTAMOEBA INVADENS

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