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Fulltext A rapid inhibitive enzyme assay for monitoring heavy metals pollution in the Juru Industrial Estate

Halmi, M.I.E., Baskaran Gunasekaran, Othman, A.R., Shukor, M.Y., Kamaruddin, K., Dahalan, F.A., et al.

Bioremediation Science and Technology Research, 2015;3(2):7-12.
MyJurnal

The volume of contaminated rivers in Malaysia continues to keep rising through the years. The
cost of instrumental monitoring is uneconomical and prohibits schedule monitoring of
contaminants particularly heavy metals. In this work, a rapid enzyme assay utilizing the
molybdenum-reducing enzyme as an inhibitive assay, prepared in crude form from the
molybdenum-reducing bacterium Serratia sp. strain DRY5 has been developed for monitoring
the heavy metals mercury, silver, copper and chromium in contaminated waters in the Juru
Industrial Estate. The crude enzyme extract transformed soluble molybdenum
(phosphomolybdate) into a deep blue solution, which is inhibited by heavy metals such as
mercury, silver, copper and chromium. The IC50 and Limits of Detection (LOD) values for
mercury, copper, silver and cadmium were 0.245, 0.298, 0.367, 0.326, and 0.124, 0.086, 0.088
and 0.094 mg L-1, respectively. The assay is rapid, and can be carried out in less than 10 minutes.
In addition, the assay can be carried out at ambient temperature. The IC50 values for these heavy
metals are more sensitive than several established assays. Water samples from various locations
in the month of November from the Juru Industrial Estate (Penang) were tested for the presence
of heavy metals using the developed assay. Enzyme activity was nearly inhibited for water
samples from several locations. The presence of heavy metals was confirmed instrumentally
using Atomic Emission Spectrometry and a Flow Injection Mercury System. The assay is rapid
and simple and can be used as a first screening method for large scale monitoring of heavy
metals.

Matched MeSH terms: Enzyme Assays
Fulltext Analysis of Genetic Variation in CYP450 Genes for Clinical Implementation

Goh LL, Lim CW, Sim WC, Toh LX, Leong KP

PLoS One, 2017;12(1):e0169233.
PMID: 28046094 DOI: 10.1371/journal.pone.0169233

BACKGROUND: Genetic determinants of drug response remain stable throughout life and offer great promise to patient-tailored drug therapy. The adoption of pharmacogenetic (PGx) testing in patient care requires accurate, cost effective and rapid genotyping with clear guidance on the use of the results. Hence, we evaluated a 32 SNPs panel for implementing PGx testing in clinical laboratories.
METHODS: We designed a 32-SNP panel for PGx testing in clinical laboratories. The variants were selected using the clinical annotations of the Pharmacogenomics Knowledgebase (PharmGKB) and include polymorphisms of CYP2C9, CYP2C19, CYP2D6, CYP3A5 and VKORC1 genes. The CYP2D6 gene allele quantification was determined simultaneously with TaqMan copy number assays targeting intron 2 and exon 9 regions. The genotyping results showed high call rate accuracy according to concordance with genotypes identified by independent analyses on Sequenome massarray and droplet digital PCR. Furthermore, 506 genomic samples across three major ethnic groups of Singapore (Malay, Indian and Chinese) were analysed on our workflow.
RESULTS: We found that 98% of our study subjects carry one or more CPIC actionable variants. The major alleles detected include CYP2C9*3, CYP2C19*2, CYP2D6*10, CYP2D6*36, CYP2D6*41, CYP3A5*3 and VKORC1*2. These translate into a high percentage of intermediate (IM) and poor metabolizer (PM) phenotypes for these genes in our population.
CONCLUSION: Genotyping may be useful to identify patients who are prone to drug toxicity with standard doses of drug therapy in our population. The simplicity and robustness of this PGx panel is highly suitable for use in a clinical laboratory.

Matched MeSH terms: Enzyme Assays
Anti-Cholinesterase Activity of Chalcone Derivatives: Synthesis, In Vitro Assay and Molecular Docking Study

Riswanto FDO, Rawa MSA, Murugaiyah V, Salin NH, Istyastono EP, Hariono M, et al.

Med Chem, 2021;17(5):442-452.
PMID: 31808389 DOI: 10.2174/1573406415666191206095032

BACKGROUND: Chalcones, originated from natural product, have been broadly studied their biological activity against various proteins which at the molecular level, are responsible for the progress of the diseases in cancer (e.g. kinases), inflammation (oxidoreductases), atherosclerosis (cathepsins receptor), and diabetes (e.g. α-glucosidase).
OBJECTIVE: Here we synthesize 10 chalcone derivatives to be evaluated their in vitro enzymatic inhibition activity against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE).
METHODS: The synthesis was carried out using Claissen-Schimdt condensation and the in vitro assay was conducted using Ellman Method.
RESULTS: Compounds 2b and 4b demonstrated as the best IC50 of 9.3 μM and 68.7 μM respectively, towards AChE and BChE inhibition. Molecular docking studies predicted that this activity might be due to the interaction of the chalcones with important amino acid residues in the binding site of AChE such as SER200 and in that of BChE, such as TRP82, SER198, TRP430, TYR440, LEU286 and VAL288.
CONCLUSION: Chalcone can be used as the scaffold for cholinesterase inhibitor, in particularly either fluorine or nitro group to be augmented at the para-position of Ring B, whereas the hydrophobic chain is necessary at the meta-position of Ring B.

Matched MeSH terms: Enzyme Assays
Fulltext Anti-inflammatory effects of Polygonum minus (Huds) extract (Lineminus™) in in-vitro enzyme assays and carrageenan induced paw edema

George A, Chinnappan S, Chintamaneni M, Kotak C V, Choudhary Y, Kueper T, et al.

BMC Complement Altern Med, 2014;14:355.
PMID: 25252832 DOI: 10.1186/1472-6882-14-355

The study was aimed to evaluate the anti-inflammatory activity of ethanolic and aqueous extracts of Polygonum minus (Huds) using in vitro and in vivo approaches.

Matched MeSH terms: Enzyme Assays
Fulltext Anti-snake venom and methanolic extract of Andrographis paniculata: a multipronged strategy to neutralize Naja naja venom acetylcholinesterase and hyaluronidase

Nayak AG, Kumar N, Shenoy S, Roche M

3 Biotech, 2020 Nov;10(11):476.
PMID: 33083200 DOI: 10.1007/s13205-020-02462-4

The study investigates the ability of methanolic extract of Andrographis paniculata (MAP) to supplement polyvalent anti-snake venom (ASV) in inhibiting neurotoxic enzyme acetylcholinesterase (AChE) and 'spreading factor' hyaluronidase from Naja naja (N.N) venom. AChE and hyaluronidase activity were measured in 100 or 200 µg of crude venom, respectively, and designated as 'control'. In Test Group I, enzyme assays were performed immediately after the addition of ASV/MAP/ASV + MAP to the venom. Inhibition of AChE by ASV (100-367 µg) was 12-17%, and of hyaluronidase (22-660 µg) was 33-41%. Under the same conditions, MAP (100-400 µg) inhibited AChE and hyaluronidase to the extent of 17-33% and 17-52%, respectively. When ASV (220 µg) and MAP (100-200 µg) were added together, AChE and hyaluronidase were inhibited to a greater extent from 39-63 to 36-44%, than when either of them was used alone. In Test Group 2, the venom was incubated with ASV/MAP/ASV + MAP for 10-30 min at 37 °C prior to the assay which enhanced AChE inhibition by 6%, 82% and 18% respectively, when compared to Test Group I. Though there was no change in inhibition of hyaluronidase in the presence of ASV, MAP could further increase the extent of inhibition by 27% and ASV + MAP upto 4%. In Test Group III, venom and substrate were incubated for 90 min and hyaluronidase activity was measured after the addition of inhibitors. Here, ASV + MAP caused increased inhibition by 69% compared to ASV alone. The study confirms the ability of phytochemicals in MAP to contribute to a multipronged strategy by supplementing, thereby augmenting the efficacy of ASV.

Matched MeSH terms: Enzyme Assays
Cold-adapted organic solvent tolerant alkalophilic family I.3 lipase from an Antarctic Pseudomonas

Ganasen M, Yaacob N, Rahman RN, Leow AT, Basri M, Salleh AB, et al.

Int J Biol Macromol, 2016 Nov;92:1266-1276.
PMID: 27506122 DOI: 10.1016/j.ijbiomac.2016.06.095

Lipolytic enzymes with cold adaptation are gaining increasing interest due to their biotechnological prospective. Previously, a cold adapted family I.3 lipase (AMS8 lipase) was isolated from an Antarctic Pseudomonas. AMS8 lipase was largely expressed in insoluble form. The refolded His-tagged recombinant AMS8 lipase was purified with 23.0% total recovery and purification factor of 9.7. The purified AMS8 lipase migrated as a single band with a molecular weight approximately 65kDa via electrophoresis. AMS8 lipase was highly active at 30°C at pH 10. The half-life of AMS8 lipase was reported at 4 and 2h under the incubation of 30 and 40°C, respectively. The lipase was stable over a broad range of pH. It showed enhancement effect in its relative activity under the presence of Li(+), Na(+), K(+), Rb(+) and Cs(+) after 30min treatment. Heavy metal ions such as Cu(2+), Fe(3+) and Zn(2+) inhibited AMS8 activity. This cold adapted alkalophilic AMS lipase was also active in various organic solvent of different polarity. These unique properties of this biological macromolecule will provide considerable potential for many biotechnological applications and organic synthesis at low temperature.

Matched MeSH terms: Enzyme Assays
Fulltext Demographic, laboratory findings and diagnostic evaluation among high risk patients with mucopolysaccharidosis in Malaysia

Omar A, Jalil JA, Shakrin NM, Ngu LH, Yunus ZM

Data Brief, 2019 Aug;25:104377.
PMID: 31516928 DOI: 10.1016/j.dib.2019.104377

This article contains information related to a recent study "Selective screening for detection of mucopolysaccharidoses (MPS) in Malaysia; A Two-year Study" Affandi et al., 2019. Any patient registered under government healthcare facilities in Malaysia and fit at least two inclusion criteria were included in this selective screening. Urine and blood from these high risk patients were obtained and analysed for glycosaminoglycans (GAGs) level before characterization using high resolution electrophoresis (HRE). Thereafter, enzyme assay for different types of MPS based on result of HRE were determined using specific substrate. Demographic data as well as laboratory findings were tabulated and analysed. The data of this study demonstrate between clinical presentation and laboratory findings among high risk patients of MPS and can be employed to improve diagnosis of MPS.

Matched MeSH terms: Enzyme Assays
Designing of promising medicinal scaffolds for Alzheimer's disease through enzyme inhibition, lead optimization, molecular docking and dynamic simulation approaches

Hassan M, Abbasi MA, Aziz-Ur-Rehman, Siddiqui SZ, Shahzadi S, Raza H, et al.

Bioorg Chem, 2019 10;91:103138.
PMID: 31446329 DOI: 10.1016/j.bioorg.2019.103138

In the designed research work, a series of 2-furoyl piperazine based sulfonamide derivatives were synthesized as therapeutic agents to target the Alzheimer's disease. The structures of the newly synthesized compounds were characterized through spectral analysis and their inhibitory potential was evaluated against butyrylcholinesterase (BChE). The cytotoxicity of these sulfonamides was also ascertained through hemolysis of bovine red blood cells. Furthermore, compounds were inspected by Lipinki Rule and their binding profiles against BChE were discerned by molecular docking. The protein fluctuations in docking complexes were recognized by dynamic simulation. From our in vitro and in silico results 5c, 5j and 5k were identified as promising lead compounds for the treatment of targeted disease.

Matched MeSH terms: Enzyme Assays
Fulltext Detection of partial G6PD deficiency using OSMMR2000-D Kit with Hb normalization

Azma, R.Z., Siti Zubaidah, M., Azlin, I., Hafiza, A., Nurasyikin, Y., Nor Hidayati, S., et al.

Medicine & Health, 2014;9(1):11-21.
MyJurnal

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most common enzyme deficiency worldwide including Malaysia. Screening of cord blood for partial G6PD deficiency is important as they are also prone to develop acute haemolysis. In this study, we determined the prevalence of partial G6PD deficient in paediatric population aged 1 month-12 years and normal term female neonates using OSMMR-D kit with haemoglobin (Hb) normalization and compare it with florescence spot test (FST). A total of 236 children, aged between between 1 month-12 years and 614 normal term female neonates were recruited for this study. Determination of normal means for G6PD activity and; cut-off points for partial and severe deficiency were determined according to WHO Working Group (1989). Determination of prevalence for partial deficiency for both groups (female patient) was done using this enzyme assay kit and findings were compared with FST. In this study, 15.7% (18/115) female children were classified as partial G6PD deficient by quantitative enzyme method (G6PD activity: 4.23-5.26U/gHb). However, FST only detected 0.9% (1/115) with minimal G6PD activity. The prevalence of partial G6PD deficiency in female neonate group was 3.42% (21/614) by enzyme assay versus 0.49% (3/614) by FST. This study concluded that our routine screening method using FST was unable to diagnose female heterozygotes. We recommend using this quantitative enzyme assay method by OSMMR-D kit since it was more sensitive in detecting G6PD deficiency in female neonates compared to FST.

Matched MeSH terms: Enzyme Assays
Detection of toluene degradation in bacteria isolated from oil contaminated soils

Ainon Hamzah, Tavakoli A, Amir Rabu

Sains Malaysiana, 2011;40:1231-1235.

Toluene (C7H8) a hydrocarbon in crude oil, is a common contaminant in soil and groundwater. In this study, the ability to degrade toluene was investigated from twelve bacteria isolates which were isolated from soil contaminated with oil. Out of 12 bacterial isolates tested, most of Pseudomonas sp. showed the capability to grow in 1 mM of toluene compared with other isolates on the third day of incubation. Based on enzyme assays towards toluene monooxygenase, Pseudomonas aeruginosa UKMP-14T and Bacillus cereus UKMP-6G were shown to have the highest ability to degrade toluene. The toluene monoxygenase activity was analysed by using two calorimetric methods, Horseradish peroxidase (HRP) and indole-indigo. Both of the methods measured the production of catechol by the enzymatic reaction of toluene monooxygenase. In the HRP assay, the highest enzyme activity was 0.274 U/mL, exhibited by Pseudomonas aeruginosa UKMP-14T. However, for indole-indigo assay, Bacillus cereus UKMP-6G produced the highest enzyme activity of 0.291 U/ml. Results from both experiments showed that Pseudomonas aeruginosa UKMP-14T and Bacillus cereus UKMP-6G were able to degrade toluene.

Matched MeSH terms: Enzyme Assays
Fulltext Development of MTH1-Binding Nucleotide Analogs Based on 7,8-Dihalogenated 7-Deaza-dG Derivatives

Shi H, Ishikawa R, Heh CH, Sasaki S, Taniguchi Y

Int J Mol Sci, 2021 Jan 28;22(3).
PMID: 33525366 DOI: 10.3390/ijms22031274

MTH1 is an enzyme that hydrolyzes 8-oxo-dGTP, which is an oxidatively damaged nucleobase, into 8-oxo-dGMP in nucleotide pools to prevent its mis-incorporation into genomic DNA. Selective and potent MTH1-binding molecules have potential as biological tools and drug candidates. We recently developed 8-halogenated 7-deaza-dGTP as an 8-oxo-dGTP mimic and found that it was not hydrolyzed, but inhibited enzyme activity. To further increase MTH1 binding, we herein designed and synthesized 7,8-dihalogenated 7-deaza-dG derivatives. We successfully synthesized multiple derivatives, including substituted nucleosides and nucleotides, using 7-deaza-dG as a starting material. Evaluations of the inhibition of MTH1 activity revealed the strong inhibitory effects on enzyme activity of the 7,8-dihalogenated 7-deaza-dG derivatives, particularly 7,8-dibromo 7-daza-dGTP. Based on the results obtained on kinetic parameters and from computational docking simulating studies, these nucleotide analogs interacted with the active site of MTH1 and competitively inhibited the substrate 8-oxodGTP. Therefore, novel properties of repair enzymes in cells may be elucidated using new compounds.

Matched MeSH terms: Enzyme Assays
Development of an inhibitive enzyme assay for copper

Shukor MY, Bakar NA, Othman AR, Yunus I, Shamaan NA, Syed MA

J Environ Biol, 2009 Jan;30(1):39-44.
PMID: 20112861

In this work the development of an inhibitive assay for copper using the molybdenum-reducing enzyme assay is presented. The enzyme is assayed using 12-molybdophosphoric acid at pH 5.0 as an electron acceptor substrate and NADH as the electron donor substrate. The enzyme converts the yellowish solution into a deep blue solution. The assay is based on the ability of copper to inhibit the molybdenum-reducing enzyme from the molybdate-reducing Serratia sp. Strain DRY5. Other heavy metals tested did not inhibit the enzyme at 10 mg l(-1). The best model with high regression coefficient to measure copper inhibition is one-phase binding. The calculated IC50 (concentration causing 50% inhibition) is 0.099 mg l(-1) and the regression coefficient is 0.98. The comparative LC50, EC50 and IC50 data for copper in different toxicity tests show that the IC50 value for copper in this study is lower than those for immobilized urease, bromelain, Rainbow trout, R. meliloti, Baker's Yeast dehydrogenase activity Spirillum volutans, P. fluorescens, Aeromonas hydrophilia and synthetic activated sludge assays. However the IC50 value is higher than those for Ulva pertusa and papain assays, but within the reported range for Daphnia magna and Microtox assays.

Matched MeSH terms: Enzyme Assays/methods*
Evaluation of Herb-Drug Interaction of Synacinn™ and Individual Biomarker through Cytochrome 450 Inhibition Assay

Ab Rahman NS, Abd Majid FA, Abd Wahid ME, Zainudin AN, Zainol SN, Ismail HF, et al.

Drug Metab Lett, 2018;12(1):62-67.
PMID: 29542427 DOI: 10.2174/1872312812666180314112457

BACKGROUND: SynacinnTM contains five standardized herbal extracts of Orthosiphon Stamineus (OS), Syzygium polyanthum (SZ), Curcuma xantorrizza (CX), Cinnamomum zeylanicum (CZ) and Andrographis paniculata (AP) and is standardized against phytochemical markers of rosmarinic acid, gallic acid, curcumin, catechin and andrographolide respectively. This herbal medicine has been used as health supplement for diabetes. SynacinnTM is recommended to be consumed as supplement to the diabetic drugs. However, herb-drug interaction of SynacinnTM polyherbal with present drugs is unknown.
METHODS: This study was designed to investigate the effect of SynacinnTM and its individual biomarkers on drug metabolizing enzymes (CYP1A2, CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6, CYP3A4 (Midazolam), CYP3A4 (Testosteron)), to assess its herb-drug interaction potential through cytochrome P450 inhibition assay. This study was conducted using liquid chromatography- tandem mass spectroscopy (LC-MS/MS) using probe substrates using human liver microsomes against CYP1A2, CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6, CYP3A4 (Midazolam) and CYP3A4 (Testosteron).
RESULTS: Result showed that SynacinnTM at maximum concentration (5000 µg/ml) 100% inhibit CYP1A2, CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6, CYP3A4 (Midazolam) and CYP3A4 (Testosteron). IC50 values determined were 0.23, 0.60, 0.47, 0.78, 1.23, 0.99, 1.01, and 0.91 mg/ml for CYP 1A2, 2B6, 2C8, 2C9, 2C19, 2D6, 3A4 (midazolam) and 3A4 (testosterone), respectively. Meanwhile, all individual biomarkers showed no, less or moderate inhibitory effect towards all the tested CYP450 except for curcumin that showed inhibition of CYP2C8 (91%), CYP2C9 (81%) and CYP2C19 (72%) at 10µM.
CONCLUSION: Curcumin was found to be an active constituent that might contribute to the inhibition of SynacinnTM against CYP2C8, CYP2C9 and CYP2C19. It can be suggested that SynacinnTM can be consumed separately from a drug known to be metabolized by all tested CYP450 enzymes.

Matched MeSH terms: Enzyme Assays
Fulltext Evaluation of the effects of Mitragyna speciosa alkaloid extract on cytochrome P450 enzymes using a high throughput assay

Kong WM, Chik Z, Ramachandra M, Subramaniam U, Aziddin RE, Mohamed Z

Molecules, 2011 Aug 29;16(9):7344-56.
PMID: 21876481 DOI: 10.3390/molecules16097344

The extract from Mitragyna speciosa has been widely used as an opium substitute, mainly due to its morphine-like pharmacological effects. This study investigated the effects of M. speciosa alkaloid extract (MSE) on human recombinant cytochrome P450 (CYP) enzyme activities using a modified Crespi method. As compared with the liquid chromatography-mass spectrometry method, this method has shown to be a fast and cost-effective way to perform CYP inhibition studies. The results indicated that MSE has the most potent inhibitory effect on CYP3A4 and CYP2D6, with apparent half-maximal inhibitory concentration (IC(50)) values of 0.78 µg/mL and 0.636 µg/mL, respectively. In addition, moderate inhibition was observed for CYP1A2, with an IC(50) of 39 µg/mL, and weak inhibition was detected for CYP2C19. The IC(50) of CYP2C19 could not be determined, however, because inhibition was <50%. Competitive inhibition was found for the MSE-treated CYP2D6 inhibition assay, whereas non-competitive inhibition was shown in inhibition assays using CYP3A4, CYP1A2 and CYP2C19. Quinidine (CYP2D6), ketoconazole (CYP3A4), tranylcypromine (CYP2C19) and furafylline (CYP1A2) were ACCESSused as positive controls throughout the experiments. This study shows that MSE may contribute to an herb-drug interaction if administered concomitantly with drugs that are substrates for CYP3A4, CYP2D6 and CYP1A2.

Matched MeSH terms: Enzyme Assays
Fulltext In vitro and in silico studies of chalcone synthase variant 2 in Boesenbergia rotunda and its substrate specificity

Sanmugavelan R, Teoh TC, Roslan N, Mohamed Z

Turk J Biol, 2018;42(3):213-223.
PMID: 30814883 DOI: 10.3906/biy-1710-107

In this study, transformation of BrCHS var 2 into B. rotunda cell suspension culture, followed by chalcone synthase enzymatic assay and HPLC analysis was conducted to investigate whether the substrate specificity for BrCHS var 2 is either cinnamoyl-CoA or p-coumaroyl-CoA. The HPLC profile showed an increase in the amount of pinocembrin chalcone when cinnamoyl-CoA and malonyl-CoA were added but not p-coumaroyl-CoA. Molecular docking was performed to explore the binding of cinnamoyl-CoA and p-coumaroyl-CoA to BrCHS var 2 receptor and the docking results showed that cinnamoyl-CoA formed numerous hydrogen bonds and more negative docked energy than p-coumaroyl-CoA. Cinnamoyl-CoA showed good interactions with Cys 164 to initiate the subsequent formation of pinocembrin chalcone, whereas the hydroxyl group of p-coumaroyl-CoA formed an unfavorable interaction with Gln 161 that caused steric hindrance to subsequent formation of naringenin chalcone. Docked conformation analysis results also showed that malonyl-CoA formed hydrogen bonding with Cys 164, His 303, and Asn 336 residues in BrCHS var 2. The results show that cinnamoyl-CoA is the preferred substrate for BrCHS var 2.

Matched MeSH terms: Enzyme Assays
Lignin biodegradation and ligninolytic enzyme studies during biopulping of Acacia mangium wood chips by tropical white rot fungi

Liew CY, Husaini A, Hussain H, Muid S, Liew KC, Roslan HA

World J Microbiol Biotechnol, 2011 Jun;27(6):1457-68.
PMID: 25187145 DOI: 10.1007/s11274-010-0598-x

White rot fungi are good lignin degraders and have the potential to be used in industry. In the present work, Phellinus sp., Daedalea sp., Trametes versicolor and Pycnoporus coccineus were selected due to their relatively high ligninolytic enzyme activity, and grown on Acacia mangium wood chips under solid state fermentation. Results obtained showed that manganese peroxidase produced is far more compared to lignin peroxidase, suggesting that MnP might be the predominating enzymes causing lignin degradation in Acacia mangium wood chips. Cellulase enzyme assays showed that no significant cellulase activity was detected in the enzyme preparation of T. versicolor and Phellinus sp. This low cellulolytic activity further suggests that these two white rot strains are of more interest in lignin degradation. The results on lignin losses showed 20-30% of lignin breakdown at 60 days of biodegradation. The highest lignin loss was found in Acacia mangium biotreated with T. versicolor after 60 days and recorded 26.9%, corresponding to the percentage of their wood weight loss recorded followed by P. coccineus. In general, lignin degradation was only significant from 20 days onwards. The overall percentage of lignin weight loss was within the range of 1.02-26.90% over the biodegradation periods. Microscopic observations conducted using scanning electron microscope showed that T. versicolor, P. coccineus, Daedalea sp. and Phellinus sp. had caused lignin degradation in Acacia mangium wood chips.

Matched MeSH terms: Enzyme Assays
Modified DNase tube test to detect DNase activity in Stenotrophomonas maltophilia

Neela V, Thomas R, Rankouhi SZR, Karunanidhi A, Shueh CS, Hamat RA, et al.

J Med Microbiol, 2012 Dec;61(Pt 12):1792-1794.
PMID: 22956752 DOI: 10.1099/jmm.0.049403-0
Matched MeSH terms: Enzyme Assays*
Fulltext New cholinesterase inhibitory constituents from Lonicera quinquelocularis

Khan D, Khan HU, Khan F, Khan S, Badshah S, Khan AS, et al.

PLoS One, 2014;9(4):e94952.
PMID: 24733024 DOI: 10.1371/journal.pone.0094952

A phytochemical investigation on the ethyl acetate soluble fraction of Lonicera quinquelocularis (whole plant) led to the first time isolation of one new phthalate; bis(7-acetoxy-2-ethyl-5-methylheptyl) phthalate (3) and two new benzoates; neopentyl-4-ethoxy-3, 5-bis (3-methyl-2-butenyl benzoate (4) and neopentyl-4-hydroxy-3, 5-bis (3-methyl-2-butenyl benzoate (5) along with two known compounds bis (2-ethylhexyl phthalate (1) and dioctyl phthalate (2). Their structures were established on the basis of spectroscopic analysis and by comparison with available data in the literature. All the compounds (1-5) were tested for their acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory activities in dose dependent manner. The IC50 (50% inhibitory effect) values of compounds 3 and 5 against AChE were 1.65 and 3.43 µM while the values obtained against BChE were 5.98 and 9.84 µM respectively. Compounds 2 and 4 showed weak inhibition profile.

Matched MeSH terms: Enzyme Assays
On optimizing the blocking step of indirect enzyme-linked immunosorbent assay for Epstein-Barr virus serology

Lim CS, Krishnan G, Sam CK, Ng CC

Clin Chim Acta, 2013 Jan 16;415:158-61.
PMID: 23043757 DOI: 10.1016/j.cca.2012.08.031

Because blocking agent occupies most binding surface of a solid phase, its ability to prevent nonspecific binding determines the signal-to-noise ratio (SNR) and reliability of an enzyme-linked immunosorbent assay (ELISA).

Matched MeSH terms: Enzyme Assays/standards*
Fulltext Optimization of an Extraction Solvent for Angiotensin-Converting Enzyme Inhibitors from Hibiscus sabdariffa L. Based on Its UPLC-MS/MS Metabolic Profiling

Salem MA, Michel HE, Ezzat MI, Okba MM, El-Desoky AM, Mohamed SO, et al.

Molecules, 2020 May 14;25(10).
PMID: 32422967 DOI: 10.3390/molecules25102307

Hibiscus species (Malvaceae) have been long used as an antihypertensive folk remedy. The aim of our study was to specify the optimum solvent for extraction of the angiotensin-converting enzyme inhibiting (ACEI) constituents from Hibiscus sabdariffa L. The 80% methanol extract (H2) showed the highest ACEI activity, which exceeds that of the standard captopril (IC50 0.01255 ± 0.00343 and 0.210 ± 0.005 µg/mL, respectively). Additionally, in a comprehensive metabolomics approach, an ultra-performance liquid chromatography (UPLC) coupled to the high resolution tandem mass spectrometry (HRMS) method was used to trace the metabolites from each extraction method. Interestingly, our comprehensive analysis showed that the 80% methanol extract was predominated with secondary metabolites from all classes including flavonoids, anthocyanins, phenolic and organic acids. Among the detected metabolites, phenolic acids such as ferulic and chlorogenic acids, organic acids such as citrate derivatives and flavonoids such as kaempferol have been positively correlated to the antihypertensive potential. These results indicates that these compounds may significantly contribute synergistically to the ACE inhibitory activity of the 80% methanol extract.

Matched MeSH terms: Enzyme Assays

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