scholarly journals The effect of tropomyosin on the adenosine triphosphatase activity of desensitized actomyosin

1967 ◽  
Vol 105 (3) ◽  
pp. 1235-1243 ◽  
Author(s):  
M. C. Schaub ◽  
S V Perry ◽  
D. J. Hartshorne
Keyword(s):  
Acetic Acid ◽  
Inhibitory Activity ◽  
Adenosine Triphosphatase ◽  
Inhibitory Effect ◽  
Tryptic Digestion ◽  
Prolonged Treatment ◽  
Thiol Groups ◽  
Protein Thiol ◽  
Adenosine Triphosphatase Activity ◽  
Inhibitory Activities

1. Tropomyosin preparations of the Bailey type, and those prepared in the presence of dithiothreitol to prevent oxidation of protein thiol groups, inhibit the Ca2+-activated adenosine triphosphatase (ATPase) of desensitized actomyosin by up to 60%. 2. The inhibitory activity of myofibrillar extracts and tropomyosin survives various agents known to denature proteins but to the action of which tropomyosin is unusually stable, namely heating at 100° and mild tryptic digestion. It is destroyed by prolonged treatment with trypsin. 3. The ethylenedioxybis-(ethyleneamino)tetra-acetic acid (EGTA)-sensitizing factor present in extracts of natural actomyosin and myofibrils could be selectively destroyed, leaving unchanged the inhibitory effect on the Ca2+-activated ATPase. There was no correlation between the EGTA-sensitizing and the Ca2+-activated inhibitory activities of tropomyosin prepared under different conditions. 4. Optimum inhibition was achieved when tropomyosin and the myosin of desensitized actomyosin were present in approximately equimolar proportions. Tropomyosin had no effect on the Ca2+-activated ATPase of myosin measured under similar conditions. 5. Evidence is presented showing that the tropomyosin binds to desensitized actomyosin under the conditions in which the ATPase is inhibited.

scholarly journals The effect of a cross-bridging thiol reagent on the catecholamine fluxes of adrenal medulla vesicles

1970 ◽  
Vol 119 (2) ◽  
pp. 265-271 ◽  
Author(s):  
W. Hasselbach ◽  
G. Taugner
Keyword(s):  
Adrenal Medulla ◽  
Initial Phase ◽  
Adenosine Triphosphatase ◽  
Thiol Groups ◽  
Adenosine Triphosphatase Activity ◽  
Bovine Adrenal Medulla ◽  
Thiol Reagent ◽  
Catecholamine Fluxes

The thiol groups of the vesicular protein of bovine adrenal medulla were allowed to react with the bifunctional thiol reagent bis-(N-maleimidomethyl) ether and with the monofunctional thiol reagent N-ethylmaleimide, and the ATP-dependent and -independent catecholamine fluxes of the modified preparations were studied. 1. During the initial phase of the reaction bis-(N-maleimidomethyl) ether blocks twice as many thiol groups as does N-ethylmaleimide at equimolar concentrations. 2. Labelling of the bis-(N-maleimidomethyl) ether–protein compound with [14C]-cysteine shows that 70–80% of the blocked thiol groups are interconnected by the bifunctional thiol reagent. 3. At a low extent of reaction (1.5mol of thiol groups/106g of protein) the catecholamine efflux is diminished. If more than 2mol of thiol groups/106g of protein are blocked, the efflux is enhanced whichever thiol reagent is applied. 4. If 2–4mol of thiol groups/106g of protein are blocked the inhibition of the catecholamine influx increases linearly with the proportion of the thiol groups blocked. 5. ATP protects the catecholamine influx and the adenosine triphosphatase activity against bis-(N-maleimidomethyl) ether poisoning somewhat less effectively than against N-ethylmaleimide poisoning.

scholarly journals Conformational changes in human lens proteins in cataract

1972 ◽  
Vol 129 (1) ◽  
pp. 97-100 ◽  
Author(s):  
John J. Harding
Keyword(s):  
Conformational Changes ◽  
Tryptic Digestion ◽  
Human Lens ◽  
Thiol Groups ◽  
Protein Thiol ◽  
Lens Proteins ◽  
Normal Human ◽  
Almost All

The reactivity of protein thiol groups in human lens and the susceptibility of the proteins to tryptic digestion were investigated. Both were found to be greater in some cataractous lenses, indicating that lens proteins have unfolded during cataractogenesis. Almost all the tyrosine in the proteins of the normal human lens reacts with tetranitromethane and is therefore probably on the outside of the major lens proteins.

Inhibitory Effect of Vitamin D2 on Adenosine-triphosphatase Activity

Nature ◽  
1966 ◽  
Vol 212 (5058) ◽  
pp. 203-204 ◽  
Author(s):  
V. B. SPIRICHEV ◽  
N. V. BLAZHEVICH
Keyword(s):  
Adenosine Triphosphatase ◽  
Inhibitory Effect ◽  
Vitamin D2 ◽  
Adenosine Triphosphatase Activity

scholarly journals THE HISTOCHEMICAL DEMONSTRATION OF ADENOSINE TRIPHOSPHATASE ACTIVITY IN MYOCARDIUM

1964 ◽  
Vol 12 (10) ◽  
pp. 740-743 ◽  
Author(s):  
N. R. NILES ◽  
J. CHAYEN ◽  
G. J. CUNNINGHAM ◽  
LUCILLE BITENSKY
Keyword(s):  
Enzymatic Activity ◽  
Adenosine Triphosphate ◽  
Adenosine Triphosphatase ◽  
Inhibitory Effect ◽  
Histochemical Demonstration ◽  
Human Myocardium ◽  
Phosphate Esters ◽  
Precise Localization ◽  
Adenosine Triphosphatase Activity

Adenosine triphosphatase has been demonstrated histochemically in rat and human myocardium. To obtain its precise localization in discrete bands, apparently corresponding to the concentration of myosin, it was necessary to modify the existing technique to obtain better preservation of unfixed tissue and maximal enzymatic activity. Thus it was necessary to increase the concentration of calcium and to effect the reaction at pH 9.4 after treatment with 2:4-dinitrophenol. The specificity of the reaction was shown by these factors, by testing with phosphate esters other than adenosine triphosphate, and by the inhibitory effect of magnesium.

9-(3,4-Dimethyl-5-pentyl-furan-2-yl) nonanoic Acid and 9-(3,4-DimethyI-5-propyl-furan-2-yl) nonanoic Acid: New Naturally Occurring Peroxidase Inhibitors

1999 ◽  
Vol 54 (11) ◽  
pp. 932-936 ◽  
Author(s):  
Claus T. Fuchs ◽  
Gerhard Spiteller
Keyword(s):  
Acetic Acid ◽  
Horseradish Peroxidase ◽  
Inhibitory Activity ◽  
Methyl Esters ◽  
Inhibitory Effect ◽  
Side Chain ◽  
Nonanoic Acid ◽  
Naturally Occurring ◽  
Indole 3 Acetic Acid

Abstract 9-(3,4-Dimethyl-5-pentyl-furan-2-yl) nonanoic acid [diMeF(9,5)] and 9-(3,4-dimethyl-5-propyl-furan-2-yl) nonanoic acid [diMeF(9,3)] and its corresponding methyl esters have been assayed for inhibitory activity on horseradish peroxidase (E C 1.11.1.17) by measuring the peroxidase-catalyse decomposition of indole-3-acetic acid. Both compounds and their meth-ylates are com petitive inhibitors to horseradish peroxidase with inhibitor constants (K1) of 50 ± 0.9 × 10-5 ᴍ respectively 5.2 ± 0.8 × 10-5 ᴍ. Development of inhibitory effect requires not only the presence of the furan heterocycle but also of a polar side chain.

Effect of aldehyde fixatives on the adenosine phosphatases and ultrastructure of Vitreoscilla

1973 ◽  
Vol 19 (9) ◽  
pp. 1059-1064 ◽  
Author(s):  
Jeffrey C. Burnham ◽  
George J. Hageage Jr.
Keyword(s):  
Enzyme Inhibition ◽  
Microscopic Examination ◽  
Adenosine Triphosphatase ◽  
Osmium Tetroxide ◽  
Electron Microscopic Examination ◽  
Inhibitory Effect ◽  
Electron Microscopic ◽  
Adenosine Triphosphatase Activity ◽  
Enzymes Inhibition ◽  
Adenosine Phosphate

A variety of aldehydes used in electron cytochemistry including glutaraldehyde, glycidaldehyde, acetaldehyde, and methanol-free formaldehyde were examined for their inhibitory effect on the adenosine phosphate hydrolases of Vitreoscilla species. Enzyme inhibition increased with increasing aldehyde concentration. Of the aldehydes tested glycidaldehyde and acetaldehyde were least inhibitory for both adenosine diphosphatase and adenosine triphosphatase activity. Significantly, a 1% concentration of glutaraldehyde inhibited over 80% of the activity of both enzymes. Inhibition by all fixatives was variably decreased by the addition of 8% sucrose. Electron-microscopic examination of Vitreoscilla species fixed with the various aldehydes revealed that both acetaldehyde and glycidaldehyde followed by osmium tetroxide postfixation gave results comparable with glutaraldehyde–osmium tetroxide fixed cells.

scholarly journals Cholinesterase and microbial inhibitory activities of Tetrapleura tetraptera

2012 ◽  
Vol 4 (2) ◽  
pp. 156-163
Author(s):  
N. E. Okoronkwo ◽  
J. O. Echeme
Keyword(s):  
Inhibitory Activity ◽  
Water Extract ◽  
Antimicrobial Activities ◽  
Inhibitory Effect ◽  
Klebsiella Pneumonia ◽  
Inhibitory Effects ◽  
Continuous Increase ◽  
Water Extracts ◽  
Tetrapleura Tetraptera ◽  
Inhibitory Activities

The cholinesterase and microbial inhibitory activities of different parts of Tetrapleura tetraptera plant were evaluated due to their local applications. The cholinesterase results revealed that the extracts showed some levels of inhibitory effects depending on the solvents used. Tetrapleura tetraptera leaves had better inhibitory effects with maximum inhibitory activity of 70.0% at a concentration of 1.00mg/l for the water extract. Tetrapleura tetraptera bark showed highest inhibitory effect of 71.05% and (84.34%) for the ethanol and chloroform extracts at concentrations of 0.5mg/l and 1.0 mg/l respectively. While for petroleum ether, T. tetraptera bark recorded 74.34% inhibitory effect at concentration of 2.0 mg/l and also showed continuous increase in inhibitory activity as the concentration increases for aqueous methanol. The results of the antimicrobial activities showed that among all the test organisms, theethanol and water extracts of the leaves, stem, bark and root of the plants had promising activity against Escherichia coli, Staphylococcus aureus, Proteus mirabilis, Pseudomonas aeruginosa and Klebsiella pneumonia bacteria and Aspergillus fumigatus and Rhizopus species fungi. There was no activity shown by the ethanol and water extracts ofthe parts of the plants with Fugarium oxysporum, Penicillium chrysogenum and Mucor species fungi. The bacteria strains were more sensitive to the tested extracts than the fungi strains.

scholarly journals Synthesis and preliminary biological evaluation of new phthalazinone derivatives with PARP-1 and cholinesterase inhibitory activities

2021 ◽  
Author(s):  
Lin Yu ◽  
Gao Chengzhi ◽  
Wang Zhuyong ◽  
Zhang Ruifeng ◽  
Chen Yajun ◽  
...  
Keyword(s):  
Inhibitory Activity ◽  
Inhibitory Effect ◽  
Docking Studies ◽  
Biological Evaluation ◽  
Ache Inhibitor ◽  
Agent Based ◽  
Potent Inhibitory Effect ◽  
Ache Inhibitory Activity ◽  
Inhibitory Activities ◽  
Parp 1

Abstract The inhibition of Poly (ADP-ribose) polymerases-1 (PARP-1) has a potentially therapeutical value for AD. In order to search for a new agent based on multitarget-directed ligands (MTDLs) strategy, a series of 21 novel compounds incorporated the respective pharmacophores of two marketed drugs, namely 4-benzyl phthalazinone moiety of PARP-1 inhibitor Olaparib and N-benzylpiperidine moiety of AChE inhibitor Donepezil, into one molecule was synthesized. The inhibitory activities of all the synthesized compounds against the enzymes PARP-1, AChE and BChE were evaluated. Among them, 30 exhibited the most potent inhibitory effect on PARP-1 enzyme (8.18±2.81 nM) and moderate BChE inhibitory activity (1.63±0.52µM), while its AChE inhibitory activity (13.48±2.15µM) was weaker than Donepezil (0.04±0.01µM). Further molecular docking studies revealed that four hydrogen bonds were formed between 30 and PARP-1 which were similar with the interactions between Olaparib and PARP-1. 30 interacted with the critical residues His438 and Trp82 of huBChE through hydrogen bond and hydrophobic interaction which were necessary for huBChE inhibitory potency. Our research gave a clue to search for new agents based on PARP-1 and cholinesterase dual-inhibited activities to treat Alzheimer's disease.

scholarly journals The relaxing protein system of striated muscle. Resolution of the troponin complex into inhibitory and calcium ion-sensitizing factors and their relationship to tropomyosin

1969 ◽  
Vol 115 (5) ◽  
pp. 993-1004 ◽  
Author(s):  
M. C. Schaub ◽  
S V Perry
Keyword(s):  
Ionic Strength ◽  
Adenosine Triphosphatase ◽  
Striated Muscle ◽  
Inhibitory Effect ◽  
Inhibitory Factor ◽  
Adenosine Triphosphatase Activity ◽  
Protein System ◽  
Maximum Inhibition ◽  
Troponin Complex ◽  
Low Ionic Strength

1. A method involving isoelectric precipitation and chromatography on SE-Sephadex (sulphoethyl-Sephadex) is described for the preparation of the troponin complex free of tropomyosin from low-ionic-strength extracts of natural actomyosin and myofibrils. 2. Purified troponin complex required tropomyosin to inhibit the Mg2+-stimulated adenosine triphosphatase activity and superprecipitation of desensitized actomyosin in the presence of ethanedioxybis(ethylamine)tetra-acetate. An upper limit of 35000 for the ‘molecular weight’ of the troponin complex was derived from the amounts required to bring about 50% of the maximum inhibition of the Mg2+-stimulated adenosine triphosphatase activity of desensitized actomyosin of known concentration. 3. In the presence of dissociating reagents the troponin complex could be dissociated into inhibitory and Ca2+-sensitizing factors, which could be isolated separately on SE-Sephadex. The inhibitory factor inhibited the Mg2+-stimulated adenosine triphosphatase activity and superprecipitation of desensitized actomyosin independently of the concentration of free Ca2+ in the medium. 4. The Ca2+-sensitizing factor changed its electrophoretic mobility on polyacrylamide gel in the presence of ethanedioxybis(ethylamine)tetra-acetate. It formed a complex with the inhibitory factor at low ionic strength and the original biological activity of the troponin complex could be restored on mixing the inhibitory factor with the Ca2+-sensitizing factor in the ratio of about 3:2. 5. Evidence is presented indicating that the ability of tropomyosin preparations to restore relaxing-protein-system activity to the troponin complex and their inhibitory effect on the Ca2+-stimulated adenosine triphosphatase activity of desensitized actomyosin are two properties of different stability to preparative procedures and tryptic digestion. This suggests that the relaxing protein system of muscle may contain another as yet uncharacterized component.

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