scholarly journals Kinetics of Crude Peroxidase from the Rind of Watermelon Fruit

2021 ◽  
pp. 20-27
Author(s):  
O. M. Iniaghe ◽  
O. Ibukun ◽  
R. E. Giwa
Keyword(s):  
Enzyme Activity ◽  
Enzyme Assay ◽  
Crude Enzyme ◽  
Redox Mediators ◽  
Alternative Source ◽  
Optimal Activity ◽  
Edo State ◽  
Kinetics Of ◽  
Assay Conditions

Aims: To study the kinetics of crude peroxidase from the rind of watermelon fruit in various assay conditions. Study Design: In vitro enzyme assay. Place and Duration of Study: Department of Biochemistry, Faculty of Life Sciences, Ambrose Alli University, Ekpoma, Edo State, Nigeria between October 2015 and January 2016. Methodology: The activity of the crude peroxidase extracted from the rind of watermelon was determined by measuring the rate of oxidation of KI at 25oC in a 3.0 ml reaction mixture which contained 2.3 ml of 25 mM - 400 mM sodium acetate buffer (pH 3.5-6.0), 0.2 ml of 2 mM KI, 0.1ml of the crude peroxidase, and 0.2 ml of varying concentrations of chlorpromazine (0.01 mM - 0.1 mM). In all cases, 0.2 ml of 0.01 mM – 1 mM H2O2 was added last to initiate the reaction. Only one parameter was varied per assay. Assays were done in five replicates. The initial velocity of the crude peroxidase for KI oxidation was determined using the absorbance at 353 nm. Results: The concentration of H2O2 that generated an optimal activity for the crude peroxidase extracted was 0.2 mM, while a pH of 5.5 was optimal for the crude enzyme. The activity of the crude enzyme increased proportionately within a buffer concentration range of 25 mM and 400 mM. Chlorpromazine (0.01 mM - 0.1 mM) proportionately increased the enzyme activity, while promethazine within a range of 0.01 mM and 0.06 mM proportionally increased the enzyme activity. Further increase in promethazine concentration beyond 0.6 mM resulted in a decreased activity of the enzyme. Conclusion: This study suggests that the Rind of watermelon is an alternative source of peroxidase. The activity of this peroxidase can be enhanced by high buffer concentrations in the presence of some redox mediators like promethazine and chlorpromazine at a pH of 5.5.

Barbiturate-induced α-amylase synthesis in barley endosperm

1970 ◽  
Vol 48 (11) ◽  
pp. 1981-1988 ◽  
Author(s):  
G. A. White
Keyword(s):  
Enzyme Activity ◽  
Gibberellic Acid ◽  
Barbituric Acid ◽  
De Novo ◽  
Carbonyl Oxygen ◽  
De Novo Synthesis ◽  
Barley Endosperm ◽  
Optimal Activity ◽  
Mammalian Liver ◽  
Kinetics Of

Phenobarbital has been found to promote the synthesis and secretion of α-amylase by embryoless barley seeds. Optimal activity was observed at a phenobarbital concentration of 1.0 mM, which promoted 39–82% (average, 57%) as much α-amylase formation as did saturating concentrations of gibberellic acid (GA3). Barley half-seeds incubated with 0.1 mM phenobarbital secreted as much protein as did those treated with 1.0 μM GA3. The kinetics of release of α-amylase from half-seeds incubated with either phenobarbital or GA3 appeared identical. Phenobarbital likely induces a de novo synthesis of α-amylase since the increase in enzyme activity was almost totally blocked by cycloheximide and 6-methylpurine. Besides phenobarbital, only cyclobarbital, amytal, hexobarbital, and thiopental showed activity among a large number of barbiturates and related drugs which were tested. In the phenobarbital molecule, the carbonyl oxygen at position 2 and the hydrogen on the nitrogen at position 3 of the barbituric acid ring are absolute requirements for activity since both 2-desoxyphenobarbital and methylphenobarbital elicited no response. Substitution of the phenyl moiety of phenobarbital with any group other than a cyclohexenyl (cyclobarbital) or an isoamyl (amytal) gave complete inactivity. Some possible mechanisms for the mode of action of phenobarbital in the barley endosperm system are discussed with particular reference to what is currently known regarding the inductive action of this barbiturate in mammalian liver.

scholarly journals Esters of quinoxaline-7-carboxylate-1,4-di-N-oxide as Trichomonas vaginalis triosephosphate isomerase inhibitors

2021 ◽  
Vol 71 (3) ◽  
pp. 485-495
Author(s):  
Isidro Palos ◽  
Rosa Moo-Puc ◽  
José Luis Vique-Sánchez ◽  
Claudia G. Benítez-Cardoza ◽  
Antonio Monge ◽  
...  
Keyword(s):  
Public Health ◽  
Enzyme Activity ◽  
Trichomonas Vaginalis ◽  
Enzyme Assay ◽  
Triosephosphate Isomerase ◽  
Public Health Problem ◽  
Pharmacological Agents ◽  
Docking Analysis ◽  
Molecular Docking Analysis

AbstractTrichomoniasis is a public health problem worldwide. Trichomoniasis treatment consists of the use of nitroimidazole derivatives; however, therapeutic ineffectiveness occurs in 5 to 20 % of the cases. Therefore, it is essential to propose new pharmacological agents against this disease. In this work, esters of quinoxaline-7-carboxylate-1,4-di-N-oxide (EQX-NO) were evaluated in in vitro assays as novel trichomonicidal agents. Additionally, an in vitro enzyme assay and molecular docking analysis against triosephosphate isomerase of Trichomonas vaginalis to confirm their mechanism of action were performed. Ethyl (compound 12) and n-propyl (compound 37) esters of quinoxaline-7-carboxy-late-1,4-di-N-oxide derivatives showed trichomonicidal activity comparable to nitazoxanide, whereas five methyl (compounds 5, 15, 19, 20 and 22), four isopropyl (compounds 28, 29, 30 and 34), three ethyl (compounds 4, 13 and 23) and one npropyl (compound 35) ester derivatives displayed activity comparable to albendazole. Compounds 6 and 20 decreased 100 % of the enzyme activity of recombinant protein triosephosphate isomerase.

Effect of pH and inhibitors on beta-amyloid fibril assembly

1996 ◽  
Vol 54 ◽  
pp. 752-753
Author(s):  
Beverly E. Maleeff ◽  
Timothy K. Hart ◽  
Stephen J. Wood ◽  
Ronald Wetzel
Keyword(s):  
Amyloid Fibril ◽  
Peptide Fragment ◽  
Hydrophobic Peptides ◽  
Amyloid Fibril Formation ◽  
Effects Of Ph ◽  
Severity Of The Disease ◽  
Kinetics Of ◽  
The Brain

Alzheimer's disease is characterized post-mortem in part by abnormal extracellular neuritic plaques found in brain tissue. There appears to be a correlation between the severity of Alzheimer's dementia in vivo and the number of plaques found in particular areas of the brain. These plaques are known to be the deposition sites of fibrils of the protein β-amyloid. It is thought that if the assembly of these plaques could be inhibited, the severity of the disease would be decreased. The peptide fragment Aβ, a precursor of the p-amyloid protein, has a 40 amino acid sequence, and has been shown to be toxic to neuronal cells in culture after an aging process of several days. This toxicity corresponds to the kinetics of in vitro amyloid fibril formation. In this study, we report the biochemical and ultrastructural effects of pH and the inhibitory agent hexadecyl-N-methylpiperidinium (HMP) bromide, one of a class of ionic micellar detergents known to be capable of solubilizing hydrophobic peptides, on the in vitro assembly of the peptide fragment Aβ.

Kinetics of Various 99mTc-Sn-Pyrophosphate Compounds in the Rat

1977 ◽  
Vol 16 (04) ◽  
pp. 157-162 ◽  
Author(s):  
C. Schümichen ◽  
B. Mackenbrock ◽  
G. Hoffmann
Keyword(s):  
Normal Saline ◽  
Half Life ◽  
Compound A ◽  
Short Half Life ◽  
Low Concentrations ◽  
The Stability ◽  
Kinetics Of ◽  
In Vitro Stability

SummaryThe bone-seeking 99mTc-Sn-pyrophosphate compound (compound A) was diluted both in vitro and in vivo and proved to be unstable both in vitro and in vivo. However, stability was much better in vivo than in vitro and thus the in vitro stability of compound A after dilution in various mediums could be followed up by a consecutive evaluation of the in vivo distribution in the rat. After dilution in neutral normal saline compound A is metastable and after a short half-life it is transformed into the other 99mTc-Sn-pyrophosphate compound A is metastable and after a short half-life in bone but in the kidneys. After dilution in normal saline of low pH and in buffering solutions the stability of compound A is increased. In human plasma compound A is relatively stable but not in plasma water. When compound B is formed in a buffering solution, uptake in the kidneys and excretion in urine is lowered and blood concentration increased.It is assumed that the association of protons to compound A will increase its stability at low concentrations while that to compound B will lead to a strong protein bond in plasma. It is concluded that compound A will not be stable in vivo because of a lack of stability in the extravascular space, and that the protein bond in plasma will be a measure of its in vivo stability.

Acquired Haemophilia: Functional Study of Antibodies to Factor VIII

1981 ◽  
Vol 45 (03) ◽  
pp. 285-289 ◽  
Author(s):  
J P Allain ◽  
A Gaillandre ◽  
D Frommel
Keyword(s):  
Factor Viii ◽  
Functional Study ◽  
Factor Viii Inhibitor ◽  
Acquired Haemophilia ◽  
Viii Inhibitor ◽  
Kinetics Of ◽  
Antibody Function ◽  
Native Plasma

SummaryFactor VIII complex and its interaction with antibodies to factor VIII have been studied in 17 non-haemophilic patients with factor VIII inhibitor. Low VIII:C and high VIIIR.Ag levels were found in all patients. VIII:WF levels were 50% of those of VTIIRrAg, possibly related to an increase of poorly aggregated and electrophoretically fast moving VIIIR:Ag oligomers.Antibody function has been characterized by kinetics of VIII :C inactivation, saturability by normal plasma and the slope of the affinity curve. Two major patterns were observed:1) Antibodies from 6 patients behaved similarly to those from haemophiliacs by showing second order inhibition kinetics, easy saturability and steep affinity slope (> 1).2) Antibodies from other patients, usually with lower titres, inactivated VIII :C according to complex order kinetics, were not saturable, and had a less steep affinity slope (< 0.7). In native plasma, or after mixing with factor VIII concentrate, antibodies of the second group did not form immune complexes with the whole factor VIII molecular complex. However, dissociation procedures did release some antibodies from apparently low molecular weight complexes formed in vivo or in vitro. For appropriate management of non-haemophilic patients with factor VIII inhibitor, it is important to determine the functional properties of their antibodies to factor VIII.

Platelet Microtubule Subunit Proteins

1979 ◽  
Vol 42 (05) ◽  
pp. 1630-1633 ◽  
Author(s):  
A G Castle ◽  
N Crawford
Keyword(s):  
Epithelial Cells ◽  
Gel Electrophoresis ◽  
Blood Platelets ◽  
Polyacrylamide Gel Electrophoresis ◽  
Polyacrylamide Gel ◽  
Lens Epithelial Cells ◽  
Molecular Weights ◽  
Kinetics Of ◽  
Microtubular Structures

SummaryBlood platelets contain microtubule proteins (tubulin and HMWs) which can be polymerised “in vitro” to form structures which resemble the microtubules seen in the intact platelet. Platelet tubulin is composed of two non-identical subunits a and p tubulin which have molecular weights around 55,000 but can be resolved in alkaline SDS-polyacrylamide gel electrophoresis. These subunits associate as dimers with sedimentation coefficients of about 5.7 S although it is not known whether the dimer protein is a homo- or hetero-dimer. The dimer tubulin binds the anti-mitotic drug colchicine and the kinetics of this binding are similar to those reported for neurotubulins. Platelet microtubules also contain two HMW proteins which appear to be essential and integral components of the fully assembled microtubule. These proteins have molecular weights greater than 200,000 daltons. Fluorescent labelled antibodies to platelet and brain tubulins stain long filamentous microtubular structures in bovine lens epithelial cells and this pattern of staining is prevented by exposing the cells to conditions known to cause depolymerisation of cell microtubules.

In-Vitro Effects of Ricinus Communis Seed Kernel Extract On Some Antioxidant And Hydrolytic Enzymes In Nymph And Adult Zonocerus Variegatus (Grasshopper)

2019 ◽  
Vol 3 (1) ◽  
pp. 129-137
Author(s):  
Gbadebo E . Adeleke ◽  
Olaniyi T. Adedosu ◽  
Rachael O. Adeyi ◽  
John O. Fatoki
Keyword(s):  
Ricinus Communis ◽  
Hydrolytic Enzymes ◽  
Crude Enzyme ◽  
Economic Losses ◽  
Seed Kernel ◽  
Zonocerus Variegatus ◽  
Sod Activity ◽  
Enzyme Preparations ◽  
In Vitro Effects

Background: Many plants have been identified for their insecticidal properties as alternatives to synthetic ones, which are toxic to untargeted organisms and environment. Ricinus communis (Castor) has been re-ported to exhibit insecticidal properties against insect pests. Zonocerus variegatus (Grasshopper) is a notable pest of several crops, and has been linked with great economic losses to farmers. The present study investigates the in-vitro toxicity of R. communis seed kernel extract (RCSKE) on the activities of selected antioxidant and hydrolytic enzymes in nymph and adult Zonocerus variegatus (Grasshopper), using cypermethrin (CYPER-M) and chlorpyrifos (CPF) as standard conventional pesticides. Methods: Seed kernel of Ricinus communis (Castor) was subjected to acidified aqueous extraction to obtain the extract (RCSKE). Crude enzyme preparations were obtained from nymph and adult Z. variegatus grass-hoppers. The in-vitro effects of different concentrations (15, 30, 45, 60, 75, 90 and 105μg/ml) each of RCSKE, CYPER-M and CPF on the activities of superoxide dismutase (SOD), catalase (CAT), acetylcholinesterase (AChE) and carboxylesterase (CES) in crude enzyme preparations were estimated spectrophotometrically. The level of statistical significance was 0.05. Results: The RCSKE significantly reduced the in-vitro SOD activity (p < 0.05) in nymph Z. variegatus at all the concentrations, whereas both CYPER-M and CPF significantly reduced the activity only at certain concentrations. The CAT activity in the nymph was significantly decreased by RCSKE and CPF at all the concentrations, but CYPER-M decreased it only at certain concentrations. In adult Z. variegatus, SOD activity was not significantly affected (p > 0.05), while CAT activity was significantly increased (p < 0.05) by the three agents at all the concentrations. The AChE and CES activities in the nymph were significantly reduced by RCSKE, CYPER-M and CPF at all the concentrations. The RCSKE and CPF significantly increased the CES activity, while CYPER-M caused a significant decrease in the activity in adult Z. variegatus. Conclusion: The seed kernel extract of Ricinus communis is an effective pesticidal agent and hence, it could be a source of biopesticide alternative with greater potential than cypermethrin and chlorpyrifos. In addition, the antioxidant, acetylcholinesterase and carboxylesterase enzymes in the nymphs of Z. variegatus grasshoppers are more susceptible to the effect of the extract than in the adult grasshoppers.

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