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Determination Kinetic Parameters of Endo-β-1,4-D-Xylanase from Abdomenal Termites with Xylan Oat and Birchwood Istri Ratnadewi, Anak Agung; Linda Faiqotul Himmah; Tri Mulyono; Wuryanti Handayani; NG. Krishnabudi; Sudarko
Indonesian Chimica Letters Vol. 1 No. 1 (2022)
Publisher : Department of Chemistry, Faculty of Mathematics and Natural Sciences, University of Jember

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (564.421 KB) | DOI: 10.19184/icl.v1i1.3

Abstract

Parameters kinetic (KM, VMax, and kCat) endo-β-1,4-D-xylanase under optimum conditions with oat spelt xylan and birchwood substrate have been investigated in this study. Hydrolysis of endo-β-1,4-D-xylanase using variation of substrate concentration (b/v) ranging from 0.2 to 1.2%. Variation of incubation time is up to 20 hours with 4 hours interval at the optimum temperature of the enzyme, 40°C. The results obtained from this study were the KM of endo-β-1,4-D-xylanase for oat spelt xylan and birchwood were 4.10 mg/ml and 0.681 mg/ml, respectively. VMax values, and kCat for oat spelt xylan substrate of 0.28 mg/ml.jam and 1.7 x 10-3 s-1. While VMax, and kCat for birchwood substrate that is 0.117 mg/U/jam and 7 x 10-4 s-1. From the results of this study we found that endo-β-1,4-D-xylanase can hydrolaze substrates which have differences solubility.
Optimum pH Buffer of Phosphate and Carbonate on The Crude Extraction of Uricase Enzyme from Goat Liver: Uricase Wuryanti Handayani; Leyla Novita Brigiyanti; Sudarko; Istri Ratnadewi, Anak Agung
Indonesian Chimica Letters Vol. 2 No. 1 (2023)
Publisher : Department of Chemistry, Faculty of Mathematics and Natural Sciences, University of Jember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.19184/icl.v2i1.365

Abstract

Uricase enzyme (urate oxidase) is an enzyme that catalyze the oxidation of uric acid in the presence of oxygen to produce allantoin, carbon dioxide (CO2) and hydrogen peroxide (H2O2). Human and primates do not have this enzyme while other mammals have it in the liver therefore the uricase enzymes are extracted from goat liver use a buffer that is compatible with the human buffer system. The type of buffer selected adjusted at the appropriate pH. The optimum uricase pH ranged from 7.5 to 9.5. The selection of buffer type is adjusted to the human buffer system. The purpose of the study was to determine the effect of the type and pH of the extraction buffer on the total activity, protein total and specific activity of crude uricase. The types of buffer selected are phosphate buffer and carbonate buffer, while the selected pH is 7.5; 8.5; and 9.5. The method used is enzyme extraction, then determination of enzyme activity and protein content to determine the specific activity of the enzyme. The results obtained the highest total enzyme activity at pH 8.5 both in carbonate buffer (0.0481 U/mL) and phosphate buffer (0.0383 U/mL). The highest protein total in carbonate buffer was at pH 9.5 (4.55 mg/mL) while the highest value was in phosphate buffer pH 8.5 (4.1 mg/mL). The specific activity of uricase pH 8.5 was carbonate buffer (0.0114 U/mg) and phosphate buffer (0.0094 U/mg). The highest uricase specific activity value was at pH 8.5 for both carbonate and phosphate buffer types and in the long term it is used as a gout therapy.
Study of The Effect of Concentration on The Level of Wetness in Chicory Leaves Using The ADSA-Overlay Method Mulyono, Tri; Ahmad Turidi; Bambang Piluharto; Dwi Indarti; Sudarko; D. Iwan Setiawan
Indonesian Chimica Letters Vol. 3 No. 1 (2024)
Publisher : Department of Chemistry, Faculty of Mathematics and Natural Sciences, University of Jember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.19184/icl.v3i1.762

Abstract

It is challenging to distinguish between farmers and insecticides. Chemicals called pesticides are applied to eliminate pests in order to boost agricultural production for farmers. Using the Axisymmetric Drop Shape Analysis (ADSA)-Overlay approach, this study attempts to investigate the impact of the pesticide fipronil concentration on the degree of wetness in mustard leaves. The size of the contact angle between the mustard leaf surface and the pesticide solution determines the pesticide's wetting action. The cosine of the contact angle (θ) between the liquid insecticide and the solid surface determines the surface tension (γ). Sessile drop is the method used to assess surface tension. Chicory is the surface area that comes into touch with pesticide drops. At 25oC samples containing 50 ppm were poured onto mustard leaves using a syringe. A digital microscope that was linked to a personal computer was used to capture sessile drop pictures. Three iterations of sessile drop imaging were conducted using samples at temperatures of 27, 29, 31, 33, and 35oC. Samples of pesticide solution at concentrations of 75, 100, 125, and 150 ppm were photographed again. The reagent 50Sc pesticide's wetting level rises with an increase in fipronil content. As concentration increases, the reagent 50Sc insecticide solution's contact angle tends to get smaller.
The Effect of Substrate Concentration and Incubation Time on The Activity of The Uricase Enzyme From Goat Liver Handayani, Wuryanti; Febriani, Nurul Afifah; Ratnadewi, Anak Agung Istri; Sudarko; Pertiwi, Andriana Kusuma
Indonesian Chimica Letters Vol. 3 No. 2 (2024)
Publisher : Department of Chemistry, Faculty of Mathematics and Natural Sciences, University of Jember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.19184/icl.v3i2.4255

Abstract

Uricase is an oxidoreductase enzyme that catalyzes the degradation of uric acid into allantoin, hydrogen peroxide, and carbon dioxide. Allantoin, the primary product of uric acid degradation, exhibits 5-10 times greater solubility in water compared to uric acid. This property underscores the importance of uricase in managing hyperuricemia, a condition characterized by elevated uric acid levels in the blood. Hyperuricemia is associated with diseases such as gout, kidney dysfunction, and hypertension. While humans and primates lack the uricase enzyme, it is naturally present in the liver of non-primate mammals, including goats. This study investigated the activity of uricase extracted from goat liver, focusing on the optimum concentration of uric acid as the substrate and incubation time necessary for achieving maximum enzymatic activity. Goat liver samples were processed using borate buffer (pH 8.5) ammonium sulfate fractionation and dialysis to isolate uricase. The enzymatic activity was evaluated at uric acid concentrations of 1.0, 1.5, 2.0, 2.5, and 3.0 mM and incubation times of 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, and 6.0 hours. The results revealed that the optimum substrate concentration for uricase was 2 mM, yielding total enzyme activity of 0.6704 U/mL and specific activity of 0.0443 U/mg. Additionally, the optimum incubation time was determined to be 5 hours, resulting in total enzyme activity of 0.8421 U/mL and specific activity of 0.0556 U/mg. These findings provide valuable insights into enhancing uricase activity and optimizing its application in therapeutic strategies for hyperuricemia management. Further research is recommended to explore the potential of uricase in clinical and pharmaceutical contexts.
Co-Authors Ahmad Turidi Anak Agung Istri Ratnadewi Andriana Kusuma Pertiwi Bambang Piluharto D. Iwan Setiawan Dwi Indarti Febriani, Nurul Afifah Istri Ratnadewi, Anak Agung Leyla Novita Brigiyanti Linda Faiqotul Himmah NG. Krishnabudi Tri Mulyono Tri Mulyono Wuryanti Handayani