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Showing 3 results for Uricase
, Mohamad Pazhang, ,
Volume 8, Issue 1 (4-2017)
Abstract
Uricase or urate oxidase is an enzyme that converts uric acid (with low solubility) to 5-hydroxyisourate and finally to allantoin. The possibility of developing some diseases like gout and kidney stones will be increased in high levels of uric acid. Thus, uricase can be used as drug enzyme to reduce uric acid levels in the blood. The low stability of proteins (such as drug enzymes) is a challenge in the use of them. There are several approaches such as use of additives for protein stabilization. In this study, E. Coli BL21 (DE3) was transformed by pET28a (+) vector carrying Aspergillus flavus uricase gene. The recombinant protein was expressed and then purified by a Ni-NTA agarose chromatography column. After purification, the thermal stability of the purified enzyme was evaluated and then it stabilized by additives. The results showed that enzyme is active and purified very well. Thermal stability results indicated that uricase maintains its stability up to 20°C and then loses its stability. The half-life of enzyme was 30minutes at 40 °. The results of enzyme stabilization by 20% (v/w) concentration of glucose and sorbitol as well as by 20 % (v/v) of glycerol showed that glucose had the most stabilization effect on the uricase among the additives. The stability (half life) of enzyme was increased more than two times in the presence of glucose. Finally, we conclude that additives like glucose which increase surface tension have the most stabilization effect on the uricase enzyme stability.
S. Daneshjoo, E.s. Dashtban Moghadam, M.r. Jafari, S.m. Rezayat Sorkhabadi, Kh. Khajeh,
Volume 10, Issue 2 (7-2019)
Abstract
Some diseases such as gout, the formation of kidney stones, Lesch-Nyhan syndrome, Heart disease, diabetes type II and metabolic syndrome are caused due to the high concentration of uric acid. Within drugs, uricase significantly decreases the level of uric acid in plasma. The production, formulation and preservation proteins need special conditions so that there was no alteration in their structure and highest activity and response, at the same time the lowest immunogenicity can be achieved.In this study, uricase from Aspergillus flavus was cloned and expressed in Escherichia coli BL21. The protein was then purified using affinity chromatography. The enzyme activity and stability were compared with the common industrial Rasburicase. Results showed higher activity and stability at different temperatures (50, 37, 25, 4, and-20°C). Since uricase has an important role in the prevention and cure of mentioned diseases, therefore, the stable form of this enzyme could be a potential candidate for drug development.
P. Shirazian, A. Ghasemi, S. Asad, M.a. Amoozgar,
Volume 10, Issue 3 (9-2019)
Abstract
Uricase (EC 1.7.3.3) was first utilized in the 1970s, to prevent the uric acid increase in the blood stream and the formation of urate crystals. Later, this enzyme was produced using recombinant DNA technology. However, immunogenic responses towards the alien protein in some patients has led to searching for new uricases with more desirable properties. Considering the interesting characteristics of enzymes of halophilic and halotolerant bacteria, the potential of 85 native Iranian halophilic bacteria isolated from Urmia salt lake for uricase production was evaluated, and the best producer was identified by means of 16S rRNA gene sequencing with more than 99% similarity to Halomonas sulfidaeris. In the following, significant physicochemical and environmental factors for optimal production of uricase by the selected strain were determined. The best combination of effective factors for the enzyme production was identified by Response Surface Methodology (RSM). The optimum enzyme production was found to be at pH=8, 34.5°C, 3% NaCl, and 7.5g/L of uric acid which resulted in the significant production of 32.5U/ml. This strain can be used in subsequent studies regarding the therapeutic application of this halotolerant enzyme.
