scholarly journals Specificity and properties of the nucleotide carrier in chromaffin granules from bovine adrenal medulla

1983 ◽  
Vol 210 (3) ◽  
pp. 789-794 ◽  
Author(s):  
A Weber ◽  
E W Westhead ◽  
H Winkler
Keyword(s):  
Amino Acid ◽  
Carboxylic Acid ◽  
Pyridoxal Phosphate ◽  
Chromaffin Granules ◽  
Inhibitory Effects ◽  
Temperature Dependent ◽  
Arginine Residues ◽  
Disulphonic Acid ◽  
Important Position ◽  
Broad Specificity

1. The influence of various substances on the uptake of [3H]ATP and [14C]-noradrenaline into isolated bovine chromaffin granules was investigated. The carrier-mediated [3H]ATP uptake is specifically inhibited by SO42-, PO43- and phosphoenolpyruvate. Compounds with carboxylic acid or sulphonic acid groups had no significant inhibitory effects on either uptake. 2. 35SO42-, 32PO43- and phosphoenol[14C]pyruvate are taken up into chromaffin granules by a temperature-dependent process that is inhibited by atractyloside, uncouplers of oxidative phosphorylation and lipid-permeant anions. The apparent Km of 35SO42- uptake is 0.4 mM. 3. These results indicate that the nucleotide carrier in chromaffin granules has a broad specificity, transporting compounds with two strong negative charges. 4. Amino acid probes influence the uptake of ATP and catecholamines differently. Pyridoxal phosphate inhibits both uptake processes, 4,4′-di-isothiocyanostilbene-2,2′-disulphonic acid preferentially blocks ATP uptake, whereas phenylglyoxal blocks only ATP transport. It is suggested that the nucleotide carrier possesses arginine residues in a functionally important position. 5. The significance of these results obtained on isolated granules for the function of chromaffin granules within the cell is discussed.

BIOCHEMICAL STUDIES ON 1-AMINOCYCLOPENTANE CARBOXYLIC ACID

1962 ◽  
Vol 40 (1) ◽  
pp. 1101-1110 ◽  
Author(s):  
K. Ahmed ◽  
P. G. Scholefield
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Carboxylic Acid ◽  
Brain Cortex ◽  
Ehrlich Ascites Carcinoma ◽  
Carcinoma Cells ◽  
Inhibitory Effects ◽  
Synthetic Amino Acid ◽  
Ehrlich Ascites ◽  
Biochemical Studies

The synthetic amino acid 1-aminocyclopentane carboxylic acid does not seem to be metabolized but is actively concentrated by slices of rat brain cortex and Ehrlich ascites carcinoma cells. Its transport into the ascites cells has much in common with that of methionine since they are both inhibited by similar groups of amino acids. Kinetic analysis of the inhibitory effects of glycine, D- and L-methionine, allyl glycine, and thienyl glycine on the transport of 1-aminocyclopentane carboxylic acid confirms the suggestion that this amino acid and methionine enter ascites cells as the result of the action of a common transport system.

BIOCHEMICAL STUDIES ON 1-AMINOCYCLOPENTANE CARBOXYLIC ACID

1962 ◽  
Vol 40 (8) ◽  
pp. 1101-1110 ◽  
Author(s):  
K. Ahmed ◽  
P. G. Scholefield
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Carboxylic Acid ◽  
Brain Cortex ◽  
Ehrlich Ascites Carcinoma ◽  
Carcinoma Cells ◽  
Inhibitory Effects ◽  
Synthetic Amino Acid ◽  
Ehrlich Ascites ◽  
Biochemical Studies

The synthetic amino acid 1-aminocyclopentane carboxylic acid does not seem to be metabolized but is actively concentrated by slices of rat brain cortex and Ehrlich ascites carcinoma cells. Its transport into the ascites cells has much in common with that of methionine since they are both inhibited by similar groups of amino acids. Kinetic analysis of the inhibitory effects of glycine, D- and L-methionine, allyl glycine, and thienyl glycine on the transport of 1-aminocyclopentane carboxylic acid confirms the suggestion that this amino acid and methionine enter ascites cells as the result of the action of a common transport system.

scholarly journals The methyltransferase METTL9 mediates pervasive 1-methylhistidine modification in mammalian proteomes

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Erna Davydova ◽  
Tadahiro Shimazu ◽  
Maren Kirstin Schuhmacher ◽  
Magnus E. Jakobsson ◽  
Hanneke L. D. M. Willemen ◽  
...  
Keyword(s):  
Amino Acid ◽  
Protein Function ◽  
Crucial Role ◽  
Complex I ◽  
Protein Modification ◽  
Zinc Binding ◽  
Functional Studies ◽  
Mitochondrial Respiratory Complex ◽  
Respiratory Complex I ◽  
Broad Specificity

AbstractPost-translational methylation plays a crucial role in regulating and optimizing protein function. Protein histidine methylation, occurring as the two isomers 1- and 3-methylhistidine (1MH and 3MH), was first reported five decades ago, but remains largely unexplored. Here we report that METTL9 is a broad-specificity methyltransferase that mediates the formation of the majority of 1MH present in mouse and human proteomes. METTL9-catalyzed methylation requires a His-x-His (HxH) motif, where “x” is preferably a small amino acid, allowing METTL9 to methylate a number of HxH-containing proteins, including the immunomodulatory protein S100A9 and the NDUFB3 subunit of mitochondrial respiratory Complex I. Notably, METTL9-mediated methylation enhances respiration via Complex I, and the presence of 1MH in an HxH-containing peptide reduced its zinc binding affinity. Our results establish METTL9-mediated 1MH as a pervasive protein modification, thus setting the stage for further functional studies on protein histidine methylation.

Isolation from atelia herbert-smithii pittier (sophoreae, leguminosae) and x-ray structure of cis-1-amino-3-hydroxymethyl-cyclobutane-1-carboxylic acid, an achiral non-protein amino acid

Tetrahedron ◽  
1987 ◽  
Vol 43 (8) ◽  
pp. 1857-1861 ◽  
Author(s):  
Geoffrey N. Austin ◽  
Peter D. Baird ◽  
Hak-Fun Chow ◽  
L.E. Fellows ◽  
G.W.J. Fleet ◽  
...  
Keyword(s):  
Amino Acid ◽  
Carboxylic Acid ◽  
Protein Amino Acid ◽  
X Ray

scholarly journals Diadenosine polyphosphate hydrolase from presynaptic plasma membranes of Torpedo electric organ

1997 ◽  
Vol 323 (3) ◽  
pp. 677-684 ◽  
Author(s):  
Jesús MATEO ◽  
Pedro ROTLLAN ◽  
Eulalia MARTI ◽  
Inmaculada GOMEZ DE ARANDA ◽  
Carles SOLSONA ◽  
...  
Keyword(s):  
Plasma Membranes ◽  
Pyridoxal Phosphate ◽  
Electric Organ ◽  
Competitive Inhibitor ◽  
Inhibitory Effect ◽  
Ic50 Value ◽  
Neural Origin ◽  
Disulphonic Acid ◽  
Torpedo Electric Organ ◽  
Enzyme Activators

The diadenosine polyphosphate hydrolase present in presynaptic plasma membranes from the Torpedo electric organ has been characterized using fluorogenic substrates of the form di-(1,N6-ethenoadenosine) 5´,5‴-P1,Pn-polyphosphate. The enzyme hydrolyses diadenosine polyphosphates (Apn A, where n = 3–5), producing AMP and the corresponding adenosine (n-1) 5´-phosphate, Ap(n-1). The Km values of the enzyme were 0.543± 0.015, 0.478±0.043 and 0.520±0.026 μM, and the Vmax values were 633±4, 592±18 and 576±45 pmol/min per mg of protein, for the etheno derivatives of Ap3A (adenosine 5´,5‴-P1,P3-triphosphate), Ap4A (adenosine 5´,5‴-P1,P4 -tetraphosphate) and Ap5A (adenosine 5´,5‴-P1,P5-pentaphosphate) respectively. Ca2+, Mg2+ and Mn2+ are enzyme activators, with EC50 values of 0.86±0.11, 1.35±0.24 and 0.58±0.10 mM respectively. The fluoride ion is an inhibitor with an IC50 value of 1.38±0.19 mM. The ATP analogues adenosine 5´-tetraphosphate and adenosine 5´-[γ-thio]triphosphate are potent competitive inhibitors and adenosine 5´-[α,β-methylene]diphosphate is a less potent competitive inhibitor, the Ki values being 0.29±0.03, 0.43±0.05 and 7.18±0.8 μM respectively. The P2-receptor antagonist pyridoxal phosphate 6-azophenyl-2´,4´-disulphonic acid behaves as a non-competitive inhibitor with a Ki value of 29.7±3.1 μM, and also exhibits a significant inhibitory effect on Torpedo apyrase activity. The effect of pH on the Km and Vmax values, together with inhibition by diethyl pyrocarbonate, strongly suggests the presence of functional histidine residues in Torpedo diadenosine polyphosphate hydrolase. The enzyme from Torpedo shows similarities with that of neural origin from neurochromaffin cells, and significant differences compared with that from endothelial vascular cells.

BASIC ESTERS OF SUBSTITUTED PYRIMIDINE-4-CARBOXYLIC ACIDS

1956 ◽  
Vol 34 (10) ◽  
pp. 1444-1446 ◽  
Author(s):  
Gordon A. Grant ◽  
Carl Von Seemann ◽  
Stanley O. Winthrop
Keyword(s):  
Amino Acid ◽  
Carboxylic Acid ◽  
Carboxylic Acids ◽  
Mucochloric Acid

A number of β-dialkylaminoethyl esters of 2,5-disubstituted pyrimidine-4-carboxylic acids have been synthesized and characterized as their hydrochlorides and in some cases as their methobromide and methiodide salts. Mucochloric acid has been condensed with S-methylisothiouronium sulphate to give 2-methylthio-5-chloropyrimidine-4-carboxylic acid, and the corresponding 5-bromo- acid has been converted to the 5-amino-acid.

scholarly journals WRAP-based nanoparticles for siRNA delivery: a SAR study and a comparison with lipid-based transfection reagents

2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Karidia Konate ◽  
Emilie Josse ◽  
Milana Tasic ◽  
Karima Redjatti ◽  
Gudrun Aldrian ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Gene Silencing ◽  
Amino Acid Composition ◽  
Acid Composition ◽  
Sirna Delivery ◽  
Cell Penetrating Peptides ◽  
Sirna Transfection ◽  
Arginine Residues ◽  
Sar Study

AbstractRecently, we designed novel amphipathic cell-penetrating peptides, called WRAP, able to transfer efficiently siRNA molecules into cells. In order to gain more information about the relationship between amino acid composition, nanoparticle formation and cellular internalization of these peptides composed of only three amino acids (leucine, arginine and tryptophan), we performed a structure–activity relationship (SAR) study. First, we compared our WRAP1 and WRAP5 peptides with the C6M1 peptide also composed of the same three amino acids and showing similar behaviors in siRNA transfection. Afterwards, to further define the main determinants in the WRAP activity, we synthesized 13 new WRAP analogues harboring different modifications like the number and location of leucine and arginine residues, the relative location of tryptophan residues, as well as the role of the α-helix formation upon proline insertions within the native WRAP sequence. After having compared the ability of these peptides to form peptide-based nanoparticles (PBNs) using different biophysical methods and to induce a targeted gene silencing in cells, we established the main sequential requirements of the amino acid composition of the WRAP peptide. In addition, upon measuring the WRAP-based siRNA transfection ability into cells compared to several non-peptide transfection agents available on the markets, we confirmed that WRAP peptides induced an equivalent level of targeted gene silencing but in most of the cases with lower cell toxicity as clearly shown in clonogenic assays.

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