Competing Methyltransferase Systems

Kerr, Sylvia J.

doi:10.1016/s0021-9258(19)45067-9

Cited by 262 publications

(32 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It is likely that SAHH activity would be elevated in WFX hens, because PEMT generates a large volume of SAH [ 30 , 63 , 64 ]. SAH inhibits methyltransferases such as PEMT [ 30 , 36 ]; therefore, SAHH hyperactivation would complement PEMT hyperactivation. Adenosine was elevated 4-fold on average in WFX hens, while dAMP (a molecule that is readily synthesized from adenosine) was slightly elevated in WFX hens ( Figure 4 D).…”

Section: Resultsmentioning

confidence: 99%

“…When evaluating this model, notice the “carbon donor” molecules (highlighted in red) that feed single-carbon units into one-carbon metabolism. For an in-depth look at one-carbon metabolism, we refer the reader to our expanded model shown in Supplementary Materials, Figure S1 [ 13 , 17 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 ].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Flaxseed Increases Animal Lifespan and Reduces Ovarian Cancer Severity by Toxically Augmenting One-Carbon Metabolism

Weston

Hales

2021

Molecules

View full text Add to dashboard Cite

We used an LC-MS/MS metabolomics approach to investigate one-carbon metabolism in the plasma of flaxseed-fed White Leghorn laying hens (aged 3.5 years). In our study, dietary flaxseed (via the activity of a vitamin B6 antagonist known as “1-amino d-proline”) induced at least 15-fold elevated plasma cystathionine. Surprisingly, plasma homocysteine (Hcy) was stable in flaxseed-fed hens despite such highly elevated cystathionine. To explain stable Hcy, our data suggest accelerated Hcy remethylation via BHMT and MS-B12. Also supporting accelerated Hcy remethylation, we observed elevated S-adenosylmethionine (SAM), an elevated SAM:SAH ratio, and elevated methylthioadenosine (MTA), in flaxseed-fed hens. These results suggest that flaxseed increases SAM biosynthesis and possibly increases polyamine biosynthesis. The following endpoint phenotypes were observed in hens consuming flaxseed: decreased physiological aging, increased empirical lifespan, 9–14% reduced body mass, and improved liver function. Overall, we suggest that flaxseed can protect women from ovarian tumor metastasis by decreasing omental adiposity. We also propose that flaxseed protects cancer patients from cancer-associated cachexia by enhancing liver function.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Flaxseed Increases Animal Lifespan and Reduces Ovarian Cancer Severity by Toxically Augmenting One-Carbon Metabolism

Weston

Hales

2021

Molecules

View full text Add to dashboard Cite

show abstract

“…Although glycine N-methyltransferase represents only one of numerous methyl-transferring enzymes, its capacity to utilize S-adenosylmethionine in liver is approximately the same as the synthesizing capacity of methionine adenosyltransferase (Kerr, 1974). It is noteworthy that the concentrations of glycine (1 mM) and S-adenosylmethionine (50M) in the liver correspond to the respective Km values of glycine N-methyltransferase (Kerr, 1972(Kerr, , 1974, whereas the methionine concentration (40-80,M) is significantly lower than the corresponding Km value of methionine adenosyltransferase (for references see Eloranta et al, 1976b). Thus it is obvious that when the concentration of methionine is increased, the rate of S-adenosylmethionine synthesis in liver is increased more than its utilization by glycine N-methyltransferase.…”

Section: Discussionmentioning

confidence: 99%

“…Competing methyltransferases may be involved in the control of its utilization. At least in the liver, glycine N-methyltransferase is such an enzyme, owing to its high activity and fairly good resistance to the inhibitory effect of S-adenosylhomocysteine (Kerr, 1972). The accumulation of S-adenosylmethionine does not seem to cause any significant changes in the synthesis and accumulation of polyamines.…”

Section: Discussionmentioning

confidence: 99%

Tissue distribution of S-adenosylmethionine and S-adenosylhomocysteine in the rat. Effect of age, sex and methionine administration on the metabolism of S-adenosylmethionine, S-adenosylhomocysteine and polyamines

Eloranta

1977

Biochemical Journal

132

View full text Add to dashboard Cite

The tissue distribution of S-adenosylmethionine, S-adenosylhomocysteine, methionine adenosyltransferase and S-adenosylhomocysteine hydrolase was explored in the rat. Also the effects of methionine administration on the accumulation of S-adenosylmethionine, S-adenosylhomocysteine and polyamines were studied in rat liver, brain and kidney. The tissue distribution of S-adenosylmethionine, S-adenosylhomocysteine, methionine adenosyltransferase and S-adenosylhomocysteine hydrolase was similar in both sexes, and was only slightly changed with age. The specific activity of S-adenosylhomocysteine hydrolase greatly exceeded that of methionine adenosyltransferase, and the concentration of S-adenosylmethionine was higher than that of S-adenosylhomocysteine in all tissues examined. However, the hepatic S-adenosylmethionine/S-adenosylhomocysteine ratio was dependent on food supply and on the age of the animal. No correlation was noticed between the activity of methionine adenosyltransferase and the concentrations of the adenosyl compounds in different tissues. Intraperitoneal administration of methionine resulted in a profound but transient increase in the hepatic concentrations of S-adenosylmethionine and S-adenosylhomocysteine. The concentration of S-adenosylmethionine was elevated also in the brain during the first 2h after methionine injection. The rise of S-adenosylmethionine concentration after methionine treatment could be diminished by simultaneous glycine administration. The results support the view that the rate-limiting factor of S-adenosylmethionine synthesis is the tissue concentration of methionine. They further suggest that glycine N-methyltransferase may have a regulatory role in the utilization of S-adenosylmethionine in the liver.

show abstract

“…whereas GNMT is almost insensitive due to its high K i AdoHcy (138,171). An additional mechanism of control for GNMT is provided by MTHF inhibition (384), allowing preservation of AdoMet when its levels are low and remethylation through MTR is needed.…”

Section: Selected Examples Of Genes and Enzymes Of Transmethylationmentioning

confidence: 99%

Mammalian Sulfur Amino Acid Metabolism: A Nexus Between Redox Regulation, Nutrition, Epigenetics, and Detoxification

Pajares

2018

Antioxidants & Redox Signaling

View full text Add to dashboard Cite

Increasing the knowledge on transsulfuration outside the liver, understanding the protein-protein interaction networks involving these enzymes, the functional role of their PTMs, or the mechanisms controlling their nucleocytoplasmic shuttling may provide further insights into the pathophysiological implications of this pathway, allowing design of new therapeutic interventions. Antioxid. Redox Signal. 29, 408-452.

show abstract

Competing Methyltransferase Systems

Cited by 262 publications

References 14 publications

Flaxseed Increases Animal Lifespan and Reduces Ovarian Cancer Severity by Toxically Augmenting One-Carbon Metabolism

Flaxseed Increases Animal Lifespan and Reduces Ovarian Cancer Severity by Toxically Augmenting One-Carbon Metabolism

Tissue distribution of S-adenosylmethionine and S-adenosylhomocysteine in the rat. Effect of age, sex and methionine administration on the metabolism of S-adenosylmethionine, S-adenosylhomocysteine and polyamines

Mammalian Sulfur Amino Acid Metabolism: A Nexus Between Redox Regulation, Nutrition, Epigenetics, and Detoxification

Contact Info

Product

Resources

About