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All Journal Indonesian Chimica Letters
Istri Ratnadewi, Anak Agung
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Chemistry

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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.
Co-Authors Leyla Novita Brigiyanti Linda Faiqotul Himmah NG. Krishnabudi Sudarko Tri Mulyono Wuryanti Handayani