Browsing by Author "Ademakinwa, Adedeji N."
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Item Biochemical characterization and kinetic studies on a purified yellow laccase from newly isolated Aureobasidium pullulans NAC8 obtained from soil containing decayed plant matter(Elsevier, 2016-06) Ademakinwa, Adedeji N.; Agboola, Femi K.The study investigated the biochemical characteristics and kinetic parameters of laccase from a newly isolated Aureobasidium pullulans NAC8 obtained from soil containing decay plant litters. This was with a view to identifying the type of laccase and its possible suitability for biotechnological applications. The fungal strain was identified as A. pullulans NAC8 by sequencing of its 5.8S rRNA and adjacent internally transcribed sequences (ITS) 1 and 2. A. pullulans NAC8 laccase was purified 2.0-fold with a yield of 59.3% and specific activity of 9.34 μmol/min/mg protein. The kinetic parameters KM, Vmax, kcat and kcat/KM for laccase with guaiacol as substrate were 1.05 ± 0.12 mM, 12.67 ± 0.55 μmol/ml/min, 25.3 × 10−1 s−1 and 2.4 × 103 M−1 s−1 respectively. Laccase exhibited maximum activity at 45 °C and optimum pH of 4.5. The enzyme showed stability at a temperature range of 45–55 °C after a 2 h incubation. The molecular weight determined on SDS–PAGE was 68.4 kDa. The enzyme was stable at 10% of all organic solvents used but displayed a loss of activity at 50%. 2.5 mM thioglycolic acid (TGA) and 0.05 mM sodium azide inactivated the enzyme. The substrate specificity was guaiacol > catechol > tannic acid > gallic acid. There was no peak observed at 610 nm and the ratio of absorbance at 280 nm and 610 was 26. This suggests a yellow laccase. The biochemical properties of A. pullulans NAC8 yellow laccase makes it potentially useful in several biotechnological applicationsItem Metabolome modulatory effects of Kigelia africana (Lam.) Benth. fruit extracts on oxidative stress, hyperlipidaemic biomarkers in STZ-induced diabetic rats and antidiabetic effects in 3T3 L1 adipocytes(Royal Pharmaceutical Society, 2020-07-25) Fagbohun, Oladapo F.; Olawoye, Babatunde; Ademakinwa, Adedeji N.; Jolayemi, Kehinde A.; Msagati, Titus A. M.Objectives The management of diabetes is considered a global problem, and a cure is yet to be discovered. This study investigated the modulatory effect of Kigelia africana fruit on oxidative stress and hyperlipidaemic biomarkers in STZinduced diabetic rats, profiled phytoconstituents using GC-TOF-MS and evaluated antidiabetic effects on 3T3 L1 adipocytes. Methods Thirty male Wistar rats (120–150 g) were divided into six groups (n = 5). Diabetes was induced by a single intraperitoneal injection of STZ (60 mg/kg) and treated with 100, 200 and 400 of hexane fraction of KA for 28 days. Immunohistochemical evaluation was carried out using avidin-biotin immunoperoxidase (ABI) method. Catalase and SOD activities as well as the levels of total protein, albumin, bilirubin, triglyceride, cholesterol, and high-density lipoprotein were measured. Key findings The expressions of oxidative stress and hyperlipidaemic biomarkers alongside fasting blood glucose concentrations were remarkedly decreased in KAtreated diabetic rats. Moreover, there was a significant increase in endocrine cell distribution, area covered with increase in b-cell mass, composition and morphology of KA-treated animals. Additionally, there was constant up-regulation in 3T3 L1 adipocytes due to the presence of phytoconstituents. Conclusion Kigelia africana fruit can act as a modulatory agent due to its ameliorative effects against oxidative stressItem Optimization of Aqueous Two-Phase Partitioning of Aureobasidium pullulans α-Amylase via Response Surface Methodology and Investigation of its Thermodynamic and Kinetic Properties(Elsevier, 2019-08-29) Ademakinwa, Adedeji N.; Agunbiade, Mayowa O.; Ayinla, Zainab A.; Agboola, Femi K.Industrial enzymes such as α-amylase must be thermostable and also easily purified/concentrated. Hence, aqueous two-phase partitioning systems (ATPS) was exploited for the partitioning of α-amylase from Aureobasidium pullulans due to its numerous advantages over conventional purification strategy. A. pullulans α-amylase was partially purified using ATPS via response surface methodology (RSM). The potentials of the ATPS-purified enzyme for possible industrial application such as resistance to thermal inactivation was investigated in comparison with the crude enzyme. PEG-6000 was the polymer of choice for ATPS as it resulted in higher purification factor (PF), %yield (Y), and partition coefficient (PC). At optimum levels (% w/v) of 20, 12 and 7.5 for PEG-6000, sodium citrate and sodium chloride respectively, maximum PF, Y and PC of 4.2, 88%, and 9.9 respectively were obtained. The response model validation and reliability were established based on the closeness between the experimented and predicted values. The kinetic and thermodynamic parameters such as Q10, t1/2, kd, D − value, Ed, of the ATPS-purified α-amylase indicated that it was thermostable at 50 to 60 °C compared to the crude α-amylase. A thermodynamically stable and ATPS-purified α-amylase from A. pullulans has properties easily applicable for most industrial processes.Item UHPLC/GC-TOF-MS metabolomics, MTT assay, and molecular docking studies reveal physostigmine as a new anticancer agent from the ethyl acetate and butanol fractions of Kigelia africana (Lam.) Benth. fruit extracts(Wiley, 2020-08-20) Fagbohun, Oladapo F.; Olawoye, Babatunde; Ademakinwa, Adedeji N.; Oriyomi, Olumayowa V.; Fagbohun, Oladoyin S.; Fadare, Olatomide A.; Msagati, Titus A.M.Kigelia africana plant is widely used as a herbal remedy in preventing the onset and the treatment of cancer-related infections. With the increase in the research interest of the plant, the specific chemical compound or metabolite that confers its anticancer properties has not been adequately investigated. The ethyl acetate and butanol fractions of the fruit extracts were evaluated by 2-(4,5-dimethylthiazol-2-yl)- 3,5-diphenyl-2H-tetrazolium bromide assay against four different cell lines, with the ethyl acetate fraction having inhibition concentration values of 0.53 and 0.42 μM against Hep G2 and HeLa cells, respectively. More than 235 phytoconstituents were profiled using UHPLC-TOF-MS, while more than 15 chemical compounds were identified using GC–MS from the fractions. Molecular docking studies revealed that physostigmine, fluazifop, dexamethasone, sulfisomidine, and desmethylmirtazapine could favorably bind at higher binding energies of –8.3, –8.6, –8.2, and –8.1 kcal/mol, respectively, better than camptothecin with a binding energy of –7.9 kcal/mol. The results of this study showed that physostigmine interacted well with topoisomerase IIα and had a high score of pharmacokinetic prediction using absorption, distribution, metabolism, excretion, and toxicity profiles, thereby suggesting that drug design using physostigmine as a base structure could serve as an alternative against the toxic side effects of doxorubicin and camptothecin.