Selective Labelling of the Methyl Carboxylate Substituents Found in the Anticodon Sequences of Some Species of Yeast Transfer RNA

1975 ◽  
Vol 53 (1) ◽  
pp. 1-10 ◽  
Author(s):  
T. D. Kennedy ◽  
B. G. Lane
Keyword(s):  
Methyl Ester ◽  
Room Temperature ◽  
Methyl Esters ◽  
Transfer Rna ◽  
Wheat Embryo ◽  
Yeast Trna ◽  
Selective Labelling

(1) By incubation in 0.1 M NaOH for 10 min at room temperature, it is possible to "saponify" some of the methyl carboxylate linkages in bulk yeast tRNA. By incubation with S-adenosyl[Me-14C]methionine and either homologous (yeast) or heterologous (wheat-embryo) enzymes, it is then possible to "re-esterify" the "saponified" tRNA and thereby effect selective labelling at 5-carboxymethyluridine [Me-14C]methyl ester residues. (2) There is also selective labelling at 2-thio-5-carboxymethyluridine [Me-14C]methyl ester residues when "saponified" yeast tRNA is incubated with S-adenosyl[Me-14C]methionine and homologous (but not heterologous) enzymes. (3) When selectively labelled yeast tRNA is hydrolyzed by RNase T1, both 5-carboxymethyluridine [Me-14C]methyl ester and its 2-thio-analogue are released as part of large oligonucleotides, each of which contains roughly 10 nucleotide residues. (4) There are at least three, and possibly four [Me-14C]-methyl ester-containing oligonucleotides released by RNase T1 digestion of selectively labelled "saponified" yeast tRNA. A comparison of the chromatographic properties of the different [Me-14C]oligonucleotides suggests that the same 5-carboxymethyluridine residues are probably targets for both homologous and heterologous enzymes. (5) The properties of the selectively labelled oligonucleotides are consistent with the view that some of them probably are derived from yeast tRNA3Glu, tRNA2Lys, and tRNA3Arg, ail of which are known to contain 5-carboxymethyl methyl esters as part of their anticodon sequences.

Synthesis of 2-thio-5-carboxymethyluridine methyl ester: a component of transfer RNA

1969 ◽  
Vol 47 (12) ◽  
pp. 1202-1203 ◽  
Author(s):  
L. Baczynskyj ◽  
K. Biemann ◽  
Maurice H. Fleysher ◽  
Ross H. Hall
Keyword(s):  
Methyl Ester ◽  
Transfer Rna ◽  
Yeast Trna ◽  
Mercuric Salt

2-Thio-5-carboxymethyluridine methyl ester was synthesized by condensing the mercuric salt of 2-thio-5-carboxymethyluracil methyl ester with 2,3,5-tri-O-benzoyl-D-ribosyl chloride. The product is identical to a nucleoside isolated from yeast tRNA

Wheat Embryo Ribonucleates. V. Generation of N2-Dimethylgnanylate When 'Fully Sequenced' Homogeneous Species of Transfer RNA are Used as Substrates for Wheat Embryo Methyltransferases

1975 ◽  
Vol 53 (6) ◽  
pp. 690-697 ◽  
Author(s):  
T. C. Kwong ◽  
B. G. Lane
Keyword(s):  
Molecular Basis ◽  
Transfer Rna ◽  
Target Site ◽  
Common Site ◽  
Tertiary Structures ◽  
Wheat Embryo ◽  
E Coli ◽  
Yeast Trna ◽  
The Subject ◽  
Random Distributions

1. When S-adenosyl[methyl-14C]methiomne and various species of transfer RNA are used as substrates for wheat embryo methyltransferases, the principal site of guanylate-N2 methylation can be shown to be a G-residue between the stems of the dihydrouridine and anticodon loops. This common site of guanylate-N2 methylation is referred to as the interstem target site.2. When the interstem target site is the non-terminal G-residue in a G-C-G-C sequence, as in the cases of Escherichia coli tRNA1Leu, tRNAIle, and tRNA3Ser, there is preponderant dimethylation to yield N2-dimethylguanylate.3. When the interstem target site is part of a U-C-G-U sequence, as in the case of E. coli tRNAtMet, there is diminished dimethylation and correspondingly increased monomethylation to yield N2-monomethylguanylate.4. When the interstem target site is the non-terminal G-residue in an A-U-G-G sequence, as in the case of yeast tRNAAsp, there is negligible dimethylation and almost exclusive monomethylation to yield N2-monomethylguanylate.5. The concerted way in which the primary, secondary, and tertiary structures of tRNA molecules might influence the efficacy of these methylations is the subject of a brief discussion. Attention is also focused on the evolutionary and molecular basis for the generally non-random distributions of methylated oligonucleotide sequences in ribosomal and transfer ribonucleates.

scholarly journals Sintesis Biodiesel Menggunakan Katalis Campuran Calcium Hydroxide dan Calcite

2021 ◽  
Vol 11 (1) ◽  
pp. 25
Author(s):  
Horasdia Saragih
Keyword(s):  
Fatty Acid ◽  
Methyl Ester ◽  
Calcium Hydroxide ◽  
Palm Oil ◽  
Room Temperature ◽  
Fatty Acid Methyl Esters ◽  
Methyl Esters ◽  
Octadecenoic Acid ◽  
Acid Methyl Ester ◽  
Acid Methyl

<p><span>Fatty acid methyl esters (FAME, biodiesel) have been synthesized using a mixture of calcium hydroxide [Ca(OH)<sub>2</sub>] and calcite [CaCO<sub>3</sub>] catalyst. The fabrication was carried out by transesterifying triglycerides from palm oil using methanol at temperature of 60<sup>o</sup>C. The mixture of calcium hydroxide [Ca(OH)<sub>2</sub>] and calcite [CaCO<sub>3</sub>] catalyst was synthesized from CaO by exposed CaO to the air at room temperature. Various transesterification times have been involved in transesterification process. Based on the results obtained, it was found that the mixture of Ca(OH)<sub>2</sub> and CaCO<sub>3</sub> has catalytic characteristics, so that it can transesterify triglycerides and produce the FAME. There are 10 types of FAME produced from the palm oil triglycerides in this transesterification. Five of this types were saturated FAME and others were unsaturated FAME. The highest concentration of FAME is cis-9-octadecenoic acid methyl ester. The longer transesterification process, the more FAME is produced. Referring to the results of this study, it shows that the mixture of Ca(OH)<sub>2</sub> and CaCO<sub>3</sub> has the potential to be used as a catalyst for synthesizing biodiesel in the future.</span></p>

Activity of Plasmin and Streptokinase-Activator on Substituted Arginine and Lysine Esters

1966 ◽  
Vol 16 (01/02) ◽  
pp. 018-031 ◽  
Author(s):  
S Sherry ◽  
Norma Alkjaersig ◽  
A. P Fletcher
Keyword(s):  
Molecular Structure ◽  
Methyl Ester ◽  
Comparative Studies ◽  
Esterase Activity ◽  
Methyl Esters ◽  
Hydrolytic Activity ◽  
The Other ◽  
Other Hand

SummaryComparative studies have been made of the esterase activity of plasmin and the streptokinase-activator of plasminogen on a variety of substituted arginine and lysine esters. Human plasmin preparations derived by different methods of activation (spontaneous in glycerol, trypsin, streptokinase (SK) and urokinase) are similar in their esterase activity; this suggests that the molecular structure required for such esterase activity is similar for all of these human plasmins. Bovine plasmin, on the other hand, differs from human plasmin in its activity on several of the substrates studied (e.g., the methyl esters of benzoyl arginine and tosyl, acetyl and carbobenzoxy lysine), a finding which supports the view that molecular differences exist between the two animal plasmins. The streptokinase-activator hydrolyzes both arginine and lysine esters but the ratios of hydrolytic activity are distinct from those of plasmin and of other activators of plasminogen. The use of benzoyl arginine methyl ester as a substrate for the measurement of the esterase activity of the streptokinase-activator is described.

scholarly journals Evaluation of 3-Methylbutanoic Acid Methyl Ester as a Factor Influencing Flavor Cleanness in Arabica Specialty Coffee

2021 ◽  
Vol 11 (12) ◽  
pp. 5413
Author(s):  
Keiko Iwasa ◽  
Harumichi Seta ◽  
Yoshihide Matsuo ◽  
Koichi Nakahara
Keyword(s):  
Methyl Ester ◽  
Methyl Esters ◽  
Acid Methyl Ester ◽  
Chemical Compounds ◽  
Gas Chromatography Mass Spectrometry ◽  
Arabica Coffee ◽  
Acid Methyl ◽  
Coffee Brew ◽  
Coffee Beans ◽  
Specialty Coffee

This paper reports on the chemical compounds in arabica coffee beans with a high Specialty Coffee Association (SCA) cupping score, especially those in specialty coffee beans. We investigated the relationship between the chemical compounds and cupping scores by considering 16 types of Coffea arabica (arabica coffee) beans from Guatemala (SCA cupping score of 76.5–89.0 points). Non-targeted gas chromatography-mass spectrometry-based chemometric profiling indicated that specialty beans with a high cupping score contained considerable amounts of methyl-esterified compounds (MECs), including 3-methylbutanoic acid methyl ester (3-MBM), and other fatty acid methyl esters. The effect of MECs on flavor quality was verified by spiking the coffee brew with 3-MBM, which was the top-ranked component, as obtained through a regression model associated with cupping scores. Notably, 3-MBM was responsible for the fresh-fruity aroma and cleanness of the coffee brew. Although cleanness is a significant factor for specialty beans, the identification of compounds that contribute to cleanness has not been reported in previous research. The chemometric profiling approach coupled with spiking test validation will improve the identification and characterization of 3-MBM commonly found in arabica specialty beans. Therefore, 3-MBM, either alone or together with MECs, can be used as a marker in coffee production.

L-leucine methyl ester stimulates insulin secretion and islet glutamate dehydrogenase

1983 ◽  
Vol 245 (4) ◽  
pp. E338-E346 ◽  
Author(s):  
P. Knudsen ◽  
H. Kofod ◽  
A. Lernmark ◽  
C. J. Hedeskov
Keyword(s):  
Insulin Secretion ◽  
Methyl Ester ◽  
Glutamate Dehydrogenase ◽  
Insulin Release ◽  
Methyl Esters ◽  
Tumor Cell Line ◽  
Fold Increase ◽  
Inhibitory Effect ◽  
Amino Acid Derivative ◽  
Mouse Pancreatic Islets

Column perifusion of collagenase-isolated mouse pancreatic islets was used to study the dynamics of insulin release in experiments lasting for several hours. The methyl esters of L-leucine and L-arginine were synthesized. Whereas L-arginine methyl ester (L-arginine OMe) had no effect, L-leucine OMe stimulated the release of insulin. The effect of L-leucine OMe was maximal at 5 mmol/liter. Whereas the Km for glucose-stimulated insulin release was unaffected by 1 mmol/liter L-leucine OMe, the maximal release of D-glucose was increased by the amino acid derivative that appeared more effective than L-leucine. L-Leucine OMe was also a potent stimulus of insulin release from the perfused mouse pancreas. In the presence of 10 mmol/liter L-glutamine, 1 mmol/liter L-leucine OMe induced a 50- to 75-fold increase in insulin release. A similar stimulatory effect was also observed in column-perifused RIN 5F cells, a cloned rat islet tumor cell line. A twofold increase in islet glutamate dehydrogenase activity was induced by 5 mmol/liter L-leucine OMe, a larger effect than that of L-leucine (P less than 0.02), whereas L-arginine OMe had a small inhibitory effect. We conclude that L-leucine OMe is a potent stimulus of insulin secretion and that its effect on the beta-cells may be exerted by activating islet glutamate dehydrogenase.

Comparison of Two Infrared Methods for the Determination of Isolated Trans Unsaturation in Fats, Oils, and Methyl Ester Derivatives

1971 ◽  
Vol 54 (6) ◽  
pp. 1288-1292
Author(s):  
Anita Huang ◽  
David Firestone
Keyword(s):  
Fatty Acids ◽  
Methyl Ester ◽  
Rapid Method ◽  
Unsaturated Fatty Acids ◽  
Methyl Esters ◽  
Tentative Method ◽  
Trans Isomers ◽  
Sample Matrix ◽  
Infrared Methods

Abstract A study was made to compare the rapid method reported by Allen with the tentative method of the American Oil Chemists’ Society for the determination of isolated (unconjugated) trans isomers of unsaturated fatty acids. The rapid method was found to be less accurate. The accuracy of the rapid method can be improved by using an oil or methyl ester matrix with the same composition as the sample matrix for the determination of K-and f-values used for calculation of per cent trans isomers. Results obtained with both methods for methyl esters were more accurate than results for vegetable oils. An analysis of variance was performed to compare the methods.

THE ACTIVATION OF PURIFIED HUMAN PLASMINOGEN IN SOLUTIONS OF ETHYLENE GLYCOLS

1963 ◽  
Vol 41 (1) ◽  
pp. 889-895 ◽  
Author(s):  
Phyllis S. Roberts
Keyword(s):  
Methyl Ester ◽  
Ethylene Glycol ◽  
Diethylene Glycol ◽  
Room Temperature ◽  
Fast Rate ◽  
Triethylene Glycol ◽  
Ethylene Glycols ◽  
Human Plasminogen ◽  
Glycol Solution ◽  
Rate Of Accumulation

Ethylene glycols have been found to allow activation of purified preparations of human plasminogen. The activity of the enzyme formed, plasmin, was measured using TAMe (p-toluene-sulphonyl-L-arginine methyl ester) as a substrate. In 50% (v/v) solutions of these compounds at pH 7.6 and 30 °C, plasmin accumulated faster in diethylene and triethylene glycols than in glycerol, but in ethylene glycol no plasmin was found. When lower concentrations of ethylene glycol (from zero to 50%) and shorter times of incubation were used, plasmin was found. With equimolar solutions (4.3 M) of glycerol and the three glycols, only diethylene glycol showed a fast rate of accumulation of plasmin. A 50% triethylene glycol solution partially inhibited the rate of spontaneous activation but stabilized the plasmin formed and therefore enzyme accumulated. At room temperature more plasmin accumulated than at higher temperatures when plasminogen was incubated in 50% triethylene glycol solution, and no plasmin was found when plasminogen was incubated at pH 7.6, 30 °C, in 50% solutions of propylene glycols, several ethers of the ethylene glycols, several polymers of various glycols, and dioxane.

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