GLYCINE METHYLTRANSFERASE

1963 ◽  
Vol 41 (1) ◽  
pp. 201-210 ◽  
Author(s):  
J. Blumenstein ◽  
G. R. Williams
Keyword(s):  
Secondary Amine ◽  
Liver Homogenate ◽  
Supernatant Fraction ◽  
Biological Oxidation ◽  
Methyl Group

The supernatant fraction of liver homogenate brings about the methylation of glycine by S-adenosylmethionine. The secondary amine formed in the reaction appears to be sarcosine. This conclusion is based on (I) the stoichiometry of the reaction, and (II) radioautography of chromatograms of the incubation products. The enzyme, glycine N-methyltransferase, was purified 80-fold, and certain of its characteristics are reported. The possible role of the enzyme in the biological oxidation of the methyl group of methionine is discussed.

GLYCINE METHYLTRANSFERASE

1963 ◽  
Vol 41 (1) ◽  
pp. 201-210 ◽  
Author(s):  
J. Blumenstein ◽  
G. R. Williams
Keyword(s):  
Secondary Amine ◽  
Liver Homogenate ◽  
Supernatant Fraction ◽  
Biological Oxidation ◽  
Methyl Group

The supernatant fraction of liver homogenate brings about the methylation of glycine by S-adenosylmethionine. The secondary amine formed in the reaction appears to be sarcosine. This conclusion is based on (I) the stoichiometry of the reaction, and (II) radioautography of chromatograms of the incubation products. The enzyme, glycine N-methyltransferase, was purified 80-fold, and certain of its characteristics are reported. The possible role of the enzyme in the biological oxidation of the methyl group of methionine is discussed.

Labile methyl group balances in the human: The role of sarcosine

Metabolism ◽  
1980 ◽  
Vol 29 (8) ◽  
pp. 707-720 ◽  
Author(s):  
S.Harvey Mudd ◽  
Michael H. Ebert ◽  
Charles R. Scriver
Keyword(s):  
Methyl Group

scholarly journals RNA binding to human METTL3-METTL14 restricts N6-deoxyadenosine methylation of DNA in vitro

2022 ◽  
Author(s):  
Shan Qi ◽  
Javier Mota ◽  
Siu-Hong Chan ◽  
Johanna Villarreal ◽  
Nan Dai ◽  
...  
Keyword(s):  
Binding Affinity ◽  
Rna Binding ◽  
Methyl Group ◽  
High Affinity ◽  
Methylation Of Dna ◽  
Dna And Rna ◽  
Close Proximity ◽  
Methylation Activity

Methyltransferase like-3 (METTL3) and METTL14 complex transfers a methyl group from S-adenosyl-L-methionine to N6 amino group of adenosine bases in RNA (m6A) and DNA (m6dA). Emerging evidence highlights a role of METTL3-METTL14 in the chromatin context, especially in processes where DNA and RNA are held in close proximity. However, a mechanistic framework about specificity for substrate RNA/DNA and their interrelationship remain unclear. By systematically studying methylation activity and binding affinity to a number of DNA and RNA oligos with different propensities to form inter- or intra-molecular duplexes or single-stranded molecules in vitro, we uncover an inverse relationship for substrate binding and methylation and show that METTL3-METTL14 preferentially catalyzes the formation of m6dA in single-stranded DNA (ssDNA), despite weaker binding affinity to DNA. In contrast, it binds structured RNAs with high affinity, but methylates the target adenosine in RNA (m6A) much less efficiently than it does in ssDNA. We also show that METTL3-METTL14-mediated methylation of DNA is largely restricted by structured RNA elements prevalent in long noncoding and other cellular RNAs.

A STUDY ON THE "IN VITRO" SYNTHESIS OF CITRULLINE: PART II. EFFECT OF GLUTAMIC ACID AND DERIVATIVES IN THE PRESENCE OF FUMARIC ACID

1964 ◽  
Vol 42 (9) ◽  
pp. 1325-1330 ◽  
Author(s):  
René Charbonneau ◽  
Louis Berlinguet
Keyword(s):  
Glutamic Acid ◽  
Rat Liver ◽  
Fumaric Acid ◽  
Liver Homogenate ◽  
Particulate Fraction ◽  
In Vitro Synthesis ◽  
System L ◽  
Acyl Derivatives

The role of N-carbamyl, N-acetyl, and L-glutamic acids with and without fumaric acid on the "in vitro" synthesis of citrulline was studied by using a particulate fraction obtained from a rat liver homogenate and a partially purified citrulline-synthesizing enzyme system. In the presence of a particulate fraction of rat liver homogenate, N-carbamyl and N-acetyl-L-glutamic acids are unable to replace L-glutamic acid, which is essential for citrulline biosynthesis. However, in the presence of fumaric acid, they both give a better synthesis of citrulline than L-glutamic acid alone. It is postulated that the acyl derivatives serve only in the transport of "activated CO2" whereas fumaric acid enters the citric acid to furnish the essential ATP molecules. Glutamic acid would be able to perform both functions. However, in the presence of a system containing partially purified citrulline-synthesizing enzymes, L-glutamic acid is unable to replace N-carbamyl and N-acetyl-L-glutamic acids with or without fumaric acid. In such a system, L-glutamic acid cannot serve in the transport of "activated CO2". It is postulated that L-glutamic acid must be acetylated prior to its utilization in this respect.With the particulate fraction of rat liver homogenate, N-allyl aspartic acid inhibits totally the synthesis of citrulline both in the presence and absence of fumaric acid with or without glutamic or N-acetyl glutamic acids. It probably interferes with the transport of "activated CO2".

Biosynthesis of 1,2-3H and 4-14C steroid sulfates of high specific activity

1970 ◽  
Vol 48 (1) ◽  
pp. 148-150 ◽  
Author(s):  
J. Torday ◽  
G. Hall ◽  
M. Schweitzer ◽  
C. J. P. Giroud
Keyword(s):  
Rat Liver ◽  
Specific Activity ◽  
Liver Homogenate ◽  
High Specific Activity ◽  
Supernatant Fraction ◽  
Metabolic Studies

A supernatant fraction of rat liver homogenate enriched with ATP was used for the biosynthesis of the ester sulfates of several 3H and 14C steroids of the pregn-4-ene series. The method provides a simple means to prepare steroid sulfates of high specific activity for use in either metabolic studies or as reference compounds in the quantification of such conjugates by isotope assays.

METHYLATION OF THE 3-OH POSITION OF CATECHOL ACIDS BY RAT LIVER AND KIDNEY PREPARATIONS

1958 ◽  
Vol 36 (5) ◽  
pp. 491-497 ◽  
Author(s):  
J. Pellerin ◽  
A. D'Iorio
Keyword(s):  
Enzymatic Activity ◽  
Rat Liver ◽  
Paper Chromatography ◽  
Reduced Glutathione ◽  
Liver Homogenate ◽  
Supernatant Fraction ◽  
Hydroxybenzoic Acid ◽  
Dihydroxybenzoic Acid ◽  
Kidney Homogenate ◽  
Liver And Kidney

3,4-Dihydroxybenzoic acid, 3,4-dihydroxyphenylacetic acid, 3,4-dihydroxymandelic acid, and 3,4-dihydroxycinnamic acid were separately incubated with L-methionine-methyl-C14 in the presence of rat liver or kidney homogenate. In each case, the radioactive metabolite separated by paper chromatography was found to have migrating properties similar to those of the 3-methoxy-4-hydroxyphenolic acid. This reaction was enhanced by the addition of ATP, Mg++, and reduced glutathione. When 3-hydroxybenzoic acid was incubated in this medium no methylated derivative was obtained. Preliminary experiments indicated that the enzymatic activity was contained mostly in the supernatant fraction. It was also noted that liver homogenate was much more active than kidney homogenate in methylating catechol acids.

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