ʟ-Phenylalanine Effect on Rat Brain Acetylcholinesterase and Na+,K+-ATPase

1998 ◽  
Vol 53 (3-4) ◽  
pp. 163-167 ◽  
Author(s):  
Stylianos Tsakiris ◽  
Panagiota Kouniniotou-Krontiri ◽  
Kleopatra H. Schulpis ◽  
John C. Stavridis
Keyword(s):  
Enzyme Activity ◽  
Cerebral Cortex ◽  
Atpase Activity ◽  
Direct Effect ◽  
Indirect Effect ◽  
Ache Activity ◽  
Brain Homogenate ◽  
Activity Increase ◽  
Low Concentrations ◽  
Brain Acetylcholinesterase

Abstract The effect of different L-phenylalanine (Phe) concentrations (0 .1-12.1 mᴍ) , on acetylcholinesterase (AChE ) and Na+,K+-ATPase activities of brain homogenate and pure enzymes, was investigated at 37 °C. AChE and Na+,K+-ATPase activities were determined according to Ellman G. L., Courtney D., Andres V. and Featherstone R. M. (1961), Biochem. Pharmacol. 7, 88 - 95 and Bowler K. and Tirri R. (1974), J. Neurochem. 23, 611-613 ) respectively, after preincubation with Phe. AChE activity in brain homogenate or in pure eel E.electricus enzyme showed a decrease, which reached up to 18% with concentrations of 0.9-12.1 mᴍ. Brain homogenate Na+,K+-ATPase activity showed an increase 16-65% with 0.24-0.9 mᴍ of Phe, while an activity increase of 60 -65% appeared with 0.9-12.1 mᴍ of Phe. Pure enzyme activity (from porcine cerebral cortex) was not affected by high Phe concentrations, while it was increased by low concentrations. The above results suggest: a) A direct effect of Phe on AChE, b) A direct effect of low Phe concentrations and an indirect effect of high ones on Na+,K+-ATPase.

ʟ-Phenylalanine Effect on Rat Diaphragm Acetylcholinesterase and Na+,K+-ATPase

1998 ◽  
Vol 53 (11-12) ◽  
pp. 1055-1060 ◽  
Author(s):  
Stylianos Tsakiris ◽  
Panagiota Kouniniotou-Krontiri ◽  
Kleopatra H. Schulpis
Keyword(s):  
Enzyme Activity ◽  
Cerebral Cortex ◽  
Atpase Activity ◽  
Ache Activity ◽  
Rat Diaphragm ◽  
Low Concentrations ◽  
Old Rats

Abstract The effect of different L-phenylalanine (Phe) concentrations (0.24-12.1 mᴍ) , on acetylcho­linesterase (AChE) and Na+,K+-ATPase activities of diaphragm homogenates from 21-day old rats and pure enzymes, was investigated at 37 °C. AChE and N a+,K+-ATPase activities were determined after preincubation with Phe. AChE activity in diaphragm homogenate or in pure eel E. electricus enzyme showed a decrease, which reached a maximum of 18% with Phe concentrations of 0.9-12.1 mᴍ. However lower Phe concentrations (0.24 mᴍ) increased the enzyme activity (by approximately 22%), only in the diaphragm homogenate. Dia­phragm-associated Na+,K+-ATPase activity showed a progressive and concentration-depen­ dent decrease, by about 30-35% in the presence of high Phe concentrations. Pure enzyme activity (from porcine cerebral cortex) was not affected by high Phe concentrations (>0.48 m M) , while it was increased by low concentrations. The above results suggest; a) A direct inactivating effect of high Phe concentrations on AChE and an indirect activating effect induced by low concentrations, b) A direct activating effect of low Phe concentrations and an indirect inactivating effect of high ones on Na+,K+-ATPase. c) The combination of high Phe concentrations effects on AChE and Na+,K+-ATPase could influence the levels of the diaphragm synaptic ACh.

EGTA-sensitive and -insensitive forms of particulate adenylate cyclase in rat cerebral cortex: regulation by divalent cations and GTP

1985 ◽  
Vol 63 (8) ◽  
pp. 1007-1016 ◽  
Author(s):  
P. V. Sulakhe
Keyword(s):  
Enzyme Activity ◽  
Cerebral Cortex ◽  
Adenylate Cyclase ◽  
Gray Matter ◽  
Rank Order ◽  
Divalent Cations ◽  
Rat Cerebral Cortex ◽  
Chloride Salt ◽  
Low Concentrations ◽  
Stimulation Of

Interactions of several divalent cations (Mn2+, Ca2+, Co2+, Sr2+, and Zn2+) with EGTA-inhibitable adenylate cyclase were investigated in washed membranes (particles) isolated from the gray matter of rat cerebral cortex. The EGTA-inhibitable (called sensitive) enzyme activity was assayed in the presence of Triton X-100 since this detergent caused a marked increase (up to 20-fold) in the enzyme activity. The effects of various divalent metals (all added as chloride salt) indicated the presence of two distinct sites called site I and site II. At low concentrations (less than micromolar) Mn2+, Co2+, and Ca2+ increased (up to 10-fold) the enzyme activity to the same extent and appeared to act via binding to site I (high affinity site). The rank order of affinity was Mn2+ ≥ Co2+ > Ca2+. Zn2+ showed the highest affinity and Sr2+ the lowest towards binding to site I; both these metals increased the enzyme activity to lesser extents than Mn2+, Co2+, or Ca2+. GTP was not required for the stimulation of this enzyme by low concentrations of Ca2+. The interaction of Mn2+ with site II (low affinity site) caused further increase in the enzyme activity, whereas Co2+, Ca2+, and Sr2+ were inhibitory at concentrations >10 μM. Isolated fraction contained loosely and tightly associated pools of calmodulin. Myelin basic protein, but not calcineurin, inhibited the EGTA-sensitive adenylate cyclase activity. The EGTA-insensitive enzyme activity was increased by norepinephrine by mechanisms that depended on GTP and was inhibited by Ca2+. The stimulation of the EGTA-insensitive enzyme modulated the Mg2+ requirement such that Mg2+ binding to the low affinity site (site II) apparently occurred with higher affinity. The likely significance of these results is discussed with regard to (i) the presence of two classes of adenylate cyclase in rat cerebral cortex gray matter and (ii) the regulation of their activities by calmodulin-requiring and GTP-requiring mechanisms.

scholarly journals Ethanol has different effects on Ca2+-transport ATPases of muscle, brain and blood platelets

1995 ◽  
Vol 312 (3) ◽  
pp. 733-737 ◽  
Author(s):  
F Mitidieri ◽  
L de Meis
Keyword(s):  
Skeletal Muscle ◽  
Endoplasmic Reticulum ◽  
Sarcoplasmic Reticulum ◽  
Atpase Activity ◽  
Blood Platelets ◽  
Activity Increase ◽  
Low Concentrations ◽  
Biphasic Effect ◽  
Transport Atpases

The effects of ethanol on different sarco/endoplasmic reticulum Ca(2+)-transport ATPases (SERCAs) were studied. In sarcoplasmic reticulum vesicles, ethanol concentrations varying from 5 to 20% promoted a progressive inhibition of Ca2+ uptake, enhancement of Ca2+ efflux, activation of the ATPase activity, increase of the enzyme phosphorylation by ATP and inhibition of enzyme phosphorylation by P1. The effects of ethanol on Ca2+ uptake and Ca2+ efflux were antagonized by Mg2+, P(i) and spermine. The increased efflux promoted by ethanol was antagonized by Ca2+ and thapsigargin. In brain and platelet vesicles a biphasic effect of ethanol was observed, so that activation occurred at low concentrations (5-10%) and inhibition at higher concentrations. The activation was not observed with the use of n-propanol and n-butanol. Different from the situation in sarcoplasmic reticulum, the decrease of the Ca2+ uptake in brain and platelet vesicles was associated with an inhibition of the ATPase activity. Mg2+ and P(i) antagonized the enhancement of Ca2+ efflux and the inhibition of Ca2+ uptake promoted by ethanol. However, thapsigargin and Ca2+ did not arrest the Ca2+ efflux promoted by ethanol in brain and platelet preparations. These results suggest that, in sarcoplasmic reticulum vesicles, ethanol uncouples the pump, promoting its activity as a Ca2+ channel. The SERCA isoform found in skeletal muscle has different properties from the isoforms found in brain and blood platelets.

´Chloride-stimulated ATPase ’ activity in Limonium vulgare Mill

1982 ◽  
Vol 299 (1097) ◽  
pp. 459-468 ◽  
Keyword(s):  
Enzyme Activity ◽  
Atpase Activity ◽  
Chloride Ions ◽  
Cautionary Tale ◽  
Monovalent Anion ◽  
Low Concentrations ◽  
Limonium Vulgare ◽  
Chloride Pump ◽  
Sea Lavender ◽  
Salt Secretion

Limonium vulgare Mill, (sea lavender) is a saltmarsh plant in whose leaves are embedded multicellular glands for the excretion of salt. Physiological studies have shown that the basis of the salt secretion mechanism appears to be salt-inducible, ATP-powered pumping of chloride ions out of gland cells. We have been investigating a ‘chloridestimulated’ ATPase activity of solubilized Limonium leafmicrosomes, which we thought was almost certainly part of a chloride pump involved in salt secretion because the properties of the enzyme activity correlated so well with the characteristics of salt secretion. Methods of purifying this activity on hexyl agarose and by selective solubilization with low concentrations of neutral detergent are presented. These and other results have made it necessary to revise our understanding of earlier findings on the purification of the ‘ Cl-stimulated ’ ATPase on Sepharose- N -caproyl galactosamine. Recent results indicate that the apparent ‘ stimulation ’ by chloride can be accounted for by an inhibition of salt-inducible ATPase activity by the ‘control’, non-Cl-, monovalent anion, benzene sulphonate, adopted because it resembles chloride yet did not support salt-secretion. Our results demonstrate some of the dangers in interpreting measurements of ion-stimulated ATPase activity, and make an instructive ‘ cautionary tale’.

The Effect of Galactose Metabolic Disorders on Rat Brain Acetylcholinesterase Activity

2000 ◽  
Vol 55 (9-10) ◽  
pp. 852-856 ◽  
Author(s):  
Stylianos Tsakiris ◽  
Kleopatra H. Schulpis
Keyword(s):  
Enzyme Activity ◽  
Ache Activity ◽  
Direct Action ◽  
Acetylcholinesterase Activity ◽  
Classical Galactosemia ◽  
Control Value ◽  
Brain Ache ◽  
Cholinergic Dysfunction ◽  
The Brain ◽  
Brain Acetylcholinesterase

Abstract To evaluate whether in classical galactosemia galactose (Gal), galactose-1-phosphate (Gal-1-P) and galactitol (Galtol) affect brain acetylcholinesterase (AChE) activity, various concentrations (1-16 mм) of these compounds were preincubated with brain homogenates of suckling rats as well as with pure eel Electroforus electricus AChE at 37 °C for 1 h. Initially, Galtol (up to 2.0 mм) increased (25%) AChE activity which decreased, thereafter, reaching the control value in high Galtol concentrations. Gal-1-P decreased gradually the enzyme activity reaching a plateau (38%), when incubated with 8-16 mM. However, when the usually found 2 mм of Galtol and 2 mм of Gal-1-P. concentrations in galactosemia were added in the incubation mixture simultaneously, brain AChE was stimulated (16%). Galtol or Gal-1-P modulated brain AChE as well as enzyme activity of E.electricus in the same way. Gal, Glucose (Glu) and glucose-1-phosphate (Glu-1-P) had no effect on AChE activity. It is suggested that Galtol as well as Gal-1-P can affect acetylcholine degradation acting directly on AChE molecule. Consequently the direct action of these substances on the enzyme might explain the brain cholinergic dysfunction in untreated galactosemia patients.

Effects of ʟ-Phenylalanine on Acetylcholinesterase, (Na+,K+)-ATPase and Mg2+-ATPase Activities in Adult Rat Whole Brain and Frontal Cortex

2001 ◽  
Vol 56 (1-2) ◽  
pp. 132-137 ◽  
Author(s):  
Stylianos Tsakiris
Keyword(s):  
Atpase Activity ◽  
Frontal Cortex ◽  
Ache Activity ◽  
Brain Homogenate ◽  
Inhibitory Effect ◽  
Whole Brain ◽  
Adult Rat ◽  
Brain Ache ◽  
Developmental Factors ◽  
Stimulation Of

Abstract The effect of different L-phenylalanine (Phe) concentrations (0.12-12.1 mм) on acetylcho­ linesterase (AChE), (Na+,K+)-ATPase and Mg2+-ATPase activities was investigated in homogenates of adult rat whole brain and frontal cortex at 37 °C. AChE, (Na+,K+)-ATPase and Mg2+-ATPase activities were determined after preincubation with Phe. AChE activity in both tissues showed a decrease up to 18% (p<0.01) with Phe. Whole brain Na+,K+-ATPase was stimulated by 30-35% (p<0.01) with high Phe concentrations, while frontal cortex Na+,K+-ATPase was stimulated by 50-55% (p<0.00l). Mg2+-ATPase activity was increased only in frontal cortex with high Phe concentrations. It is suggested that: a) The inhibitory effect of Phe on brain AChE is not influenced by developmental factors, while the stimulation of Phe on brain Na+,K+-ATPase is indeed affected; b) The stimulatory effect of Phe on rat whole brain Na+,K+-ATPase is decreased with age; c) Na+,K+-ATPase is selectively more stimulated by high Phe concentrations in frontal cortex than in whole brain homogenate; d) High (toxic) Phe concentrations can affect Mg2+-ATPase activity in frontal cortex, but not in whole brain, thus modulating the amount of intracellular Mg2+.

Faktor-Faktor yang Mempengaruhi Minat Beli Produk Makanan Olahan Halal pada Konsumen

2018 ◽  
Vol 8 (3) ◽  
pp. 250
Author(s):  
Saniatun Nurhasah ◽  
Jono M Munandar ◽  
Muhammad Syamsun
Keyword(s):  
Food Safety ◽  
Direct Effect ◽  
Indirect Effect ◽  
Purchase Intention ◽  
Brand Image ◽  
Perceived Value ◽  
Perceived Quality ◽  
Market Potential ◽  
Purchasing Intention ◽  
Positive Direct

<p><em>ABSTRACT</em></p><p><em>Indonesia is one of the largest Moslem population countries in the world. It leads to the increasing of halal product demand in Indonesia. The awareness to consume halal product becomes a large market potential for producers to produce their halal products. Nowadays, halal is not only purely about religion matter, but also about business and trade. The objective of this study is to investigate the factors affecting customers on purchasing halal buying interest on processed food. We use a purposive sampling method with 109 respondents who are customers of the supermarkets and minimarkets in Bogor City/District, Indonesia. While data analysis is done by SEM-PLS method, this study uses brand image, perceived quality, perceived value, halal certification, health reason, halal awareness, and halal marketing as the factors which are affecting the halal purchase intention of the customers. The result showed that health reason, halal awareness, and perceived value have a significant and positive direct effect on purchasing intention. Halal marketing also shows a significant and positive effect on purchasing intention. While halal marketing shows a negative and significant effect on purchasing intention. The food safety, halal certification, brand image, and perceived quality show the same effect which has no direct effect on purchasing intention. Furthermore, food safety has an indirect effect on purchasing intention through health reason. Halal certification has an indirect effect on minat beli through brand image variable. Meanwhile, brand image and perceived quality have an indirect effect through perceived value variable on purchasing intention.</em></p><p><em><br /></em></p><p>ABSTRAK</p><p>Indonesia adalah salah satu negara dengan populasi Muslim terbesar di dunia. Hal ini menyebabkan meningkatnya permintaan produk halal di Indonesia. Kesadaran untuk mengkonsumsi produk halal menjadi potensi pasar yang besar bagi produsen untuk memproduksi produk halal mereka. Saat ini, halal tidak hanya murni soal agama, tapi juga soal bisnis dan perdagangan. Tujuan dari penelitian ini adalah untuk mengetahui faktor-faktor yang mempengaruhi minat pelanggan dalam membeli pada makanan olahan halal. Kami menggunakan metode voluntery sampling dengan 109 responden yang merupakan pelanggan supermarket dan minimarket di Kota/Kabupaten Bogor, Indonesia. Sedangkan analisis data dilakukan dengan metode SEM-PLS. Penelitian ini menggunakan citra merek, persepsi kualitas, persepsi nilai, sertifikasi halal, kesehatan, kesadaran halal, dan Pemasaran halal sebagai faktor yang mempengaruhi niat pembelian halal pelanggan. Hasil penelitian menunjukkan bahwa kesadaran halal, alasan kesehatan, dan persepsi nilai berpengaruh positif dan signifikan terhadap niat beli. Pemasaran halal juga menunjukkan efek positif dan signifikan terhadap niat beli. Sedangkan pemasaran halal menunjukkan efek negatif dan signifikan terhadap niat beli. Keamanan pangan, sertifikasi halal, citra merek, dan kualitas yang dirasakan menunjukkan efek yang sama yang tidak berpengaruh langsung pada niat beli. Selanjutnya, keamanan pangan berpengaruh tidak langsung terhadap niat beli melalui alasan kesehatan. Sertifikasi halal memiliki efek tidak langsung terhadap niat beli melalui variabel citra merek. Sedangkan citra merek dan persepsi kualitasmemiliki pengaruh tidak langsung melalui persepsi nilai variable terhadap niat beli.</p>

scholarly journals Arcopilus aureus MaC7A as a New Source of Resveratrol: Assessment of Amino Acid Precursors, Volatiles, and Fungal Enzymes for Boosting Resveratrol Production in Batch Cultures

2021 ◽  
Vol 11 (10) ◽  
pp. 4583
Author(s):  
Nemesio Villa-Ruano ◽  
Luis Ángel Morales-Mora ◽  
Jenaro Leocadio Varela-Caselis ◽  
Antonio Rivera ◽  
María de los Ángeles Valencia de Ita ◽  
...  
Keyword(s):  
Amino Acid ◽  
Filamentous Fungi ◽  
Hydrolytic Enzymes ◽  
Glucanase Activity ◽  
Fungal Enzymes ◽  
Activity Increase ◽  
Batch Cultures ◽  
Low Concentrations ◽  
Chemical Factors ◽  
Amino Acid Precursors

The chemical factors that regulate the synthesis of resveratrol (RV) in filamentous fungi are still unknown. This work reports on the RV production by Arcopilus aureus MaC7A under controlled conditions and the effect of amino acid precursors (PHE and TYR), monoterpenes (limonone, camphor, citral, thymol, menthol), and mixtures of hydrolytic enzymes (Glucanex) as elicitors for boosting fungal RV. Batch cultures with variable concentrations of PHE and TYR (50–500 mg L−1) stimulated RV production from 127.9 ± 4.6 to 221.8 ± 5.2 mg L−1 in basic cultures developed in PDB (pH 7) added with 10 g L−1 peptone at 30 °C. Maximum levels of RV and biomass were maintained during days 6–8 under these conditions, whereas a dramatic RV decrease was observed from days 10–12 without any loss of biomass. Among the tested volatiles, citral (50 mg L−1) enhanced RV production until 187.8 ± 2.2 mg L−1 in basic cultures, but better results were obtained with Glucanex (100 mg L−1; 198.3 ± 7.6 mg L−1 RV). Optimized batch cultures containing TYR (200 mg L−1), citral (50 mg L−1), thymol (50 mg L−1), and Glucanex (100 mg L−1) produced up to 237.6 ± 4.7 mg L−1 of RV. Our results suggest that low concentrations of volatiles and mixtures of isoenzymes with β-1, 3 glucanase activity increase the biosynthesis of fungal RV produced by A. aureus MaC7A in batch cultures.

Serum Cholinesterase Variants: Examination of Several Differential Inhibitors, Salts, and Buffers Used to Measure Enzyme Activity

1971 ◽  
Vol 17 (3) ◽  
pp. 183-191 ◽  
Author(s):  
Philip J Garry
Keyword(s):  
Enzyme Activity ◽  
Sodium Fluoride ◽  
Phosphate Buffer ◽  
Divalent Cations ◽  
Kinetic Studies ◽  
Competitive Inhibitor ◽  
Serum Cholinesterase ◽  
Low Concentrations

Abstract Dibucaine, used as a differential inhibitor with acetyl-, propionyl-, and butyrylthiocholine as substrate, clearly identified the "usual" and "atypical" serum cholinesterases. Succinylcholine was also used successfully as a differential inhibitor with butyrylthiocholine as substrate. Sodium fluoride, used as a differential inhibitor, gave conflicting results, depending on whether Tris or phosphate buffer was used in the assay. Mono- and divalent cations (NaCl, KCl, MgCl2, CaCl2, and BaCl2) activated the "usual" and inhibited the "atypical" enzyme at low concentrations. The "usual" enzyme had the same activity in 0.05 mol of Tris or phosphate buffer per liter, while the heterozygous and "atypical" enzymes showed 12 and 42% inhibition, respectively, when assayed in the phosphate buffer. Kinetic studies showed the phosphate acted as a competitive inhibitor of "atypical" enzyme. Km values, determined for "usual" and "atypical" enzymes, were 0.057 and 0.226 mmol/liter, respectively, with butyrylthiocholine as substrate.

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