Mechanism of inhibition of succinate oxidase by products of oxidation of o-dihydroxycoumarins

1980 ◽  
Vol 45 (2) ◽  
pp. 641-652
Author(s):  
Petr Zbořil
Keyword(s):  
Inhibitory Activity ◽  
Oxidase Activity ◽  
Enzyme Preparation ◽  
Inhibitory Effects ◽  
Anaerobic Conditions ◽  
Long Period ◽  
Mechanism Of Inhibition ◽  
Intermediary Product ◽  
Succinate Oxidase ◽  
By Products

Semiquinone is an intermediary product of the oxidation of daphnetin (7,8-dihydroxycoumarin) and esculetin (6,7-dihydroxycoumarin) by diphenol oxidase; its concentration rapidly decreases. When the oxidation is effected by ferricytochrome c, the concentration of the semiquinone remains practically constant for a long period. Similarly, the ability of the products of daphnetin oxidation by diphenol oxidase to inhibit succinate oxidase activity in mitochondrial fragments rapidly decreases with time; the decrease is considerably slower in the case of cytochrome c. The inhibitory activity of the product decreases with time also during esculetin oxidation by ferricyanide. This indicates that the inhibitory effects must be ascribed predominantly to the semiquinone, the quinone is less efficient. The inhibition of succinate oxidase or succinate dehydrogenase was strongly decreased when the enzyme preparation of Keilin and Hartree was incubated with esculetin and ferricyanide in the presence of KCN or under anaerobic conditions. This demonstrates that the reaction of the inhibitor with the enzyme either involves subsequent oxidations or that the inhibitor preferentially reacts with the oxidized form of the sensitive component of the respiratory chain. The second alternative is very little probable since there is no correlation between the degree of inhibition and the binding of the inhibitor to mitochondrial fragments.

Inhibitory effects of bioaccessible anthocyanins and procyanidins from apple, red grape, cinnamon on α-amylase, α-glucosidase and lipase

2020 ◽  
pp. 1-9
Author(s):  
Pınar Ercan ◽  
Sedef Nehir El
Keyword(s):  
Inhibitory Activity ◽  
Digestive Enzymes ◽  
Positive Control ◽  
Anthocyanin Content ◽  
Inhibitory Effects ◽  
Total Anthocyanin ◽  
Total Anthocyanin Content ◽  
Before And After ◽  
Red Grape

Abstract. The goals of this study were to determine and evaluate the bioaccessibility of total anthocyanin and procyanidin in apple (Amasya, Malus communis), red grape (Papazkarası, Vitis vinifera) and cinnamon (Cassia, Cinnamomum) using an in vitro static digestion system based on human gastrointestinal physiologically relevant conditions. Also, in vitro inhibitory effects of these foods on lipid (lipase) and carbohydrate digestive enzymes (α-amylase and α-glucosidase) were performed with before and after digested samples using acarbose and methylumbelliferyl oleate (4MUO) as the positive control. While the highest total anthocyanin content was found in red grape (164 ± 2.51 mg/100 g), the highest procyanidin content was found in cinnamon (6432 ± 177.31 mg/100 g) (p < 0.05). The anthocyanin bioaccessibilities were found as 10.2 ± 1%, 8.23 ± 0.64%, and 8.73 ± 0.70% in apple, red grape, and cinnamon, respectively. The procyanidin bioaccessibilities of apple, red grape, and cinnamon were found as 17.57 ± 0.71%, 14.08 ± 0.74% and 18.75 ± 1.49%, respectively. The analyzed apple, red grape and cinnamon showed the inhibitory activity against α-glucosidase (IC50 544 ± 21.94, 445 ± 15.67, 1592 ± 17.58 μg/mL, respectively), α-amylase (IC50 38.4 ± 7.26, 56.1 ± 3.60, 3.54 ± 0.86 μg/mL, respectively), and lipase (IC50 52.7 ± 2.05, 581 ± 54.14, 49.6 ± 2.72 μg/mL), respectively. According to our results apple, red grape and cinnamon have potential to inhibit of lipase, α-amylase and α-glucosidase digestive enzymes.

Impairment of Platelet Aggregation by Echis colorata Venom Mediated by L-Amino Acid Oxidase or H2O2

1982 ◽  
Vol 48 (03) ◽  
pp. 277-282 ◽  
Author(s):  
I Nathan ◽  
A Dvilansky ◽  
T Yirmiyahu ◽  
M Aharon ◽  
A Livne
Keyword(s):  
Hydrogen Peroxide ◽  
Amino Acid ◽  
Platelet Aggregation ◽  
Snake Venom ◽  
Oxidase Activity ◽  
Enzyme Preparation ◽  
Acid Oxidase ◽  
Crude Venom ◽  
Amino Acid Oxidase ◽  
Hemostatic Disorders

SummaryEchis colorata bites cause impairment of platelet aggregation and hemostatic disorders. The mechanism by which the snake venom inhibits platelet aggregation was studied. Upon fractionation, aggregation impairment activity and L-amino acid oxidase activity were similarly separated from the crude venom, unlike other venom enzymes. Preparations of L-amino acid oxidase from E.colorata and from Crotalus adamanteus replaced effectively the crude E.colorata venom in impairment of platelet aggregation. Furthermore, different treatments known to inhibit L-amino acid oxidase reduced in parallel the oxidase activity and the impairment potency of both the venom and the enzyme preparation. H2O2 mimicked characteristically the impairment effects of L-amino acid oxidase and the venom. Catalase completely abolished the impairment effects of the enzyme and the venom. It is concluded that hydrogen peroxide formed by the venom L-amino acid oxidase plays a role in affecting platelet aggregation and thus could contribute to the extended bleeding typical to persons bitten by E.colorata.

scholarly journals Synthesis, Molecular Docking Analysis and Biological Evaluations of Saccharide-Modified Thiadiazole Sulfonamide Derivatives

2021 ◽  
Vol 22 (11) ◽  
pp. 5482
Author(s):  
Zuo-Peng Zhang ◽  
Ye Zhong ◽  
Zhen-Bin Han ◽  
Lin Zhou ◽  
Hua-Sheng Su ◽  
...  
Keyword(s):  
Inhibitory Activity ◽  
Human Cancer ◽  
Carbonic Anhydrases ◽  
Inhibitory Effects ◽  
Docking Analysis ◽  
Human Cancer Cell Lines ◽  
Hypoxic Conditions ◽  
Ca Ix ◽  
Topological Polar Surface Area ◽  
Ht 29

A series of saccharide-modified thiadiazole sulfonamide derivatives has been designed and synthesized by the “tail approach” and evaluated for inhibitory activity against carbonic anhydrases II, IX, and XII. Most of the compounds showed high topological polar surface area (TPSA) values and excellent enzyme inhibitory activity. The impacts of some compounds on the viability of HT-29, MDA-MB-231, and MG-63 human cancer cell lines were examined under both normoxic and hypoxic conditions, and they showed certain inhibitory effects on cell viability. Moreover, it was found that the series of compounds had the ability to raise the pH of the tumor cell microenvironment. All the results proved that saccharide-modified thiadiazole sulfonamides have important research prospects for the development of CA IX inhibitors.

scholarly journals Characterization of Protein Hydrolysates from Fish Discards and By-Products from the North-West Spain Fishing Fleet as Potential Sources of Bioactive Peptides

Marine Drugs ◽  
2021 ◽  
Vol 19 (6) ◽  
pp. 338
Author(s):  
Andreia Henriques ◽  
José A. Vázquez ◽  
Jesus Valcarcel ◽  
Rogério Mendes ◽  
Narcisa M. Bandarra ◽  
...  
Keyword(s):  
Inhibitory Activity ◽  
Bioactive Peptides ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Protein Hydrolysates ◽  
Scavenging Activity ◽  
North West ◽  
Chelating Activity ◽  
The North ◽  
By Products

Fish discards and by-products can be transformed into high value-added products such as fish protein hydrolysates (FPH) containing bioactive peptides. Protein hydrolysates were prepared from different parts (whole fish, skin and head) of several discarded species of the North-West Spain fishing fleet using Alcalase. All hydrolysates had moisture and ash contents lower than 10% and 15%, respectively. The fat content of FPH varied between 1.5% and 9.4% and had high protein content (69.8–76.6%). The amino acids profiles of FPH are quite similar and the most abundant amino acids were glutamic and aspartic acids. All FPH exhibited antioxidant activity and those obtained from Atlantic horse mackerel heads presented the highest 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, reducing power and Cu2+ chelating activity. On the other hand, hydrolysates from gurnard heads showed the highest ABTS radical scavenging activity and Fe2+ chelating activity. In what concerns the α-amylase inhibitory activity, the IC50 values recorded for FPH ranged between 5.70 and 84.37 mg/mL for blue whiting heads and whole Atlantic horse mackerel, respectively. α-Glucosidase inhibitory activity of FPH was relatively low but all FPH had high Angiotensin Converting Enzyme (ACE) inhibitory activity. Considering the biological activities, these FPH are potential natural additives for functional foods or nutraceuticals.

Growth-Inhibiting Properties of Xylem Exudate From Vitis vinifera

1995 ◽  
Vol 22 (1) ◽  
pp. 7 ◽  
Author(s):  
JA Campbell ◽  
BR Loveys ◽  
VWK Lee ◽  
S Strother
Keyword(s):  
Vitis Vinifera ◽  
Inhibitory Activity ◽  
Lemna Minor ◽  
Growth Inhibitor ◽  
Inhibitory Effect ◽  
Vitis Vinifera L ◽  
Inhibitory Effects ◽  
Inhibitor Activity ◽  
Xylem Exudate ◽  
Growth Inhibiting

An inhibitory effect on the growth of Lemna minor L. cultures has been demonstrated in xylem exudate from Vitis vinifera L. var. Waltham Cross bled from canes cut near the time of budburst. Most inhibitory activity was detected up to the time of maximal daily exudation, which corresponded closely with budburst. After this time the inhibitory activity rapidly disappeared. A similar pattern occurred in each of the 3 years of the study, 1988-1990. Using ultrafiltration, it was shown that most of the growth inhibitor activity of the crude exudate was located in the 0.5-10 kDa fraction. This fraction exhibited a seasonal variation in its bioactivity similar to that ofthe crude exudate samples. The 0.5-10 kDa fraction was found to contain abscisic acid but not in a sufficient quantity to account for the inhibitory effects. When chromatographically separated fractions corresponding to oligosaccharides were pooled, biological activity equivalent to that of the crude exudate was retained, which provides evidence that the inhibitor is possibly an oligosaccharide.

scholarly journals Drug-induced conversion of liver haem into modified porphyrins. Evidence for two classes of products

1980 ◽  
Vol 187 (1) ◽  
pp. 285-288 ◽  
Author(s):  
F De Matteis ◽  
A H Gibbs
Keyword(s):  
Inhibitory Activity ◽  
Spectral Properties ◽  
Drug Induced ◽  
Mechanism Of Inhibition ◽  
Green Pigments

A porphyrin with inhibitory activity towards protohaem ferro-lyase (EC 4.99.1.1) was isolated from the liver of mice given either griseofulvin or isogriseofulvin. This porphyrin resembles closely in chromatographic and spectral properties the inhibitory pigment isolated after treatment with 3,5-diethoxycarbonyl-1,4-dihydrocollidine, but differs from other green pigments that do not inhibit protohaem ferro-lyase. A hypothesis is proposed to account for the differences in properties between the two groups of pigments and for the mechanism of inhibition of the enzyme.

scholarly journals Biotransformation of 2,4,6,8,10,12-Hexanitro-2,4,6,8,10,12-Hexaazaisowurtzitane (CL-20) by Denitrifying Pseudomonas sp. Strain FA1

2003 ◽  
Vol 69 (9) ◽  
pp. 5216-5221 ◽  
Author(s):  
Bharat Bhushan ◽  
Louise Paquet ◽  
Jim C. Spain ◽  
Jalal Hawari
Keyword(s):  
Nitrous Oxide ◽  
Enzyme Preparation ◽  
Electron Transfer Reaction ◽  
Garden Soil ◽  
Resting Cells ◽  
Anaerobic Conditions ◽  
Intact Cells ◽  
Cell Biomass ◽  
Membrane Enzyme ◽  
Enzyme Catalyzed Reactions

ABSTRACT The microbial and enzymatic degradation of a new energetic compound, 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL-20), is not well understood. Fundamental knowledge about the mechanism of microbial degradation of CL-20 is essential to allow the prediction of its fate in the environment. In the present study, a CL-20-degrading denitrifying strain capable of utilizing CL-20 as the sole nitrogen source, Pseudomonas sp. strain FA1, was isolated from a garden soil. Studies with intact cells showed that aerobic conditions were required for bacterial growth and that anaerobic conditions enhanced CL-20 biotransformation. An enzyme(s) involved in the initial biotransformation of CL-20 was shown to be membrane associated and NADH dependent, and its expression was up-regulated about 2.2-fold in CL-20-induced cells. The rates of CL-20 biotransformation by the resting cells and the membrane-enzyme preparation were 3.2 ± 0.1 nmol h−1 mg of cell biomass−1 and 11.5 ± 0.4 nmol h−1 mg of protein−1, respectively, under anaerobic conditions. In the membrane-enzyme-catalyzed reactions, 2.3 nitrite ions (NO2 −), 1.5 molecules of nitrous oxide (N2O), and 1.7 molecules of formic acid (HCOOH) were produced per reacted CL-20 molecule. The membrane-enzyme preparation reduced nitrite to nitrous oxide under anaerobic conditions. A comparative study of native enzymes, deflavoenzymes, and a reconstituted enzyme(s) and their subsequent inhibition by diphenyliodonium revealed that biotransformation of CL-20 is catalyzed by a membrane-associated flavoenzyme. The latter catalyzed an oxygen-sensitive one-electron transfer reaction that caused initial N denitration of CL-20.

scholarly journals Antimicrobial activity of fifteen Italian honeys against Paenibacillus larvae ATCC 9545

2018 ◽  
Vol 68 (4) ◽  
pp. 547 ◽  
Author(s):  
S. SAGONA ◽  
B. TURCHI ◽  
F. FRATINI ◽  
M. GIUSTI ◽  
B. TORRACCA ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Glucose Oxidase ◽  
Inhibitory Activity ◽  
Oxidase Activity ◽  
Gluconic Acid ◽  
Total Flavonoid ◽  
Paenibacillus Larvae ◽  
Economic Losses ◽  
Total Phenolic ◽  
Honey Sample

Currently, American Foulbrood (AFB) represents one of the most important problems for beekeepers, due to economic losses and to the absence of an effective therapeutic treatment. The aim of this work was to characterize fifteen Italian honeys in order to assess their inhibitory activity against Paenibacillus larvae ATCC 9545. Each honey was analyzed for the activity of the following enzymes: glucose oxidase and catalase. Moreover, melissopalynological analysis and other biochemical parameters, namely gluconic acid, total phenolic and total flavonoid contents were determined. For each honey, the Minimum Inhibitory Concentration (M.I.C.) and the Minimum Bactericidal Concentration (M.B.C.) against P. larvae were determined. All tested honey samples had an inhibitory activity on P. larvae. In particular, the lowest M.I.C. and M.B.C. values (53.8 mg/mL and 107.5 mg/mL, respectively) were recorded for an Arbutus honey sample. Arbutus honeys also had the highest gluconic acid and total phenolic contents (12.6 ± 1.7 g/kg and 243.2 ± 25.1 mg/kg, respectively) and the highest glucose oxidase activity (13.0 ± 1.9 nM H2O2/min). Dark honeys, including Arbutus, seem to have a higher gluconic acid content and a higher antimicrobial activity. Thus, honey characterization, including colour and physico-chemical characteristics (e.g. gluconic acid concentration, total phenolic and total flavonoid contents, glucose oxidase activity), could be crucial for the assessment of its employment against P. larvae.

scholarly journals Stimulation of the alternative oxidase of Neurospora crassa by Nucleoside phosphates

1980 ◽  
Vol 188 (1) ◽  
pp. 141-144 ◽  
Author(s):  
J Vanderleyden ◽  
C Peeters ◽  
H Verachtert ◽  
H Bertrand
Keyword(s):  
Neurospora Crassa ◽  
Oxidase Activity ◽  
Alternative Oxidase ◽  
Purine Nucleoside ◽  
Submitochondrial Particles ◽  
Fold Stimulation ◽  
Succinate Oxidase ◽  
Stimulation Of

The alternative-oxidase-mediated succinate oxidase activity of Neurospora crassa decreases drastically when mitochondria are fractionated into submitochondrial particles or treated with deoxycholate. The activity, however, can be completely restored in the presence of nucleoside 5′-monophosphates. The purine nucleoside 5′-monophosphates are more effective than the pyrimidine homologues. 5′-GMP gives a 10-fold stimulation of the alternative-oxidase-mediated succinate oxidase activity in submitochondrial particles. A comparison is made with the results obtained earlier with Moniliella tomentosa [Hanssens & Verachtert (1976) J. Bacteriol. 125, 825–835; Vanderleyden, Van Den Eynde & Verachtert (1980) Biochem. J. 186, 309–316].

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