Sequential immobilization of urease to glycidyl methacrylate grafted sodium alginate

WOS: 000284566200006Objective of this study is to realize appropriate enzyme immobilization onto a suitable support material and to develop a model which enables reactions catalyzed with different enzymes arranged in order. Thence, this model was potential for developing a multi-enzyme system. The reactions need more than one enzyme can be realized using immobilized form of them and the enzymes will be in one support at wanted activities. In this study, sodium alginate was used as immobilization material and glycidyl methacrylate was grafted onto sodium alginate. Thus reactive epoxy groups were added to sodium alginate which also has carboxyl groups. Average molecular weight of sodium alginate was determined using Ubbelohde viscosimetri. The molecular mass of sodium alginate was calculated as 15,900 Da. Graft polymerization was made in two steps. Firstly, sodium alginate was activated with benzophenone using UV-light at 254 nm. Secondly, glycidyl methacrylate was grafted under UV-light at 365 nm onto activated sodium alginate. Grafted glycidyl methacrylate was determined gravimetric and titrimetric. Additional groups after grafting were showed with FT-IR spectrum. 1-Ethyl-3-(3-dimetylaminopropyl)-carbodiimide was used for immobilization urease from carboxyl groups at pH 5.0. Suitable 1-ethyl-3-(3-dimetylaminopropyl)-carbodiimide/-COOH ratio was found 1/10 and immobilized product activity was 197 U/g support. Reaction medium pH was 8.0 for immobilization from epoxy group. Optimum immobilization reaction time was found as 2 h and immobilized product activity was 285 U/g support. Sequential immobilization of urease to glycidyl methacrylate grafted sodium alginate was made from -COOH and epoxy groups, respectively. (C) 2010 Elsevier B.V. All rights reserved.Ege University Research FoundationEge University [2003 FEN 017]This project has been funded by the Ege University Research Foundation under Project 2003 FEN 017

Encapsulation of PEG-Urease/PEG-AlaDH within sheep erythrocytes and determination of the system's activity in lowering blood levels of urea in animal models

WOS: 000248721800005PubMed ID: 17701485Urease and AlaDH enzymes immobilized on active PEG derivatives were encapsulated at different ratios within sheep erythrocytes and their activity, encapsulation yields and erythrocyte recovery levels were assessed. Encapsulated derivatives were administered at given dosages and at given intervals to sheep having raised blood urea levels as a result of addition of urea to their feed, and the lowering of their blood urea levels and the change in the amount of ammonia were followed. Results were analyzed using day related NPar. Wilcoxon Signet Ranks test. It was found that 1 ml of PEG-enzyme preparation comprising PEG-urease/PEG-AlaDH at an activity ratio of 3/9 U:U/ml remained active for a period of 2 days, whereas 1 ml erythrocyte preparation, prepared under the same conditions and containing PEG-urease/PEG-AlaDH at an activity ratio of 2.15/4.5 U:U/ml, showed activity for a period of 6 days. It was shown that a single dose achieved a daily decrease of 21.7-61.6 mg/L in the blood urea level, and created no significant increase in the blood ammonia levels. No antigenic effect was observed for the PEG-enzyme preparations in the immunological test carried out