Results enzyme layer preparation

We prepared sandwich type of laminates by using different type of PC based membranes as the outer membrane. The inner membrane was the PES membrane which was described in the previous section. The enzyme layer prepared by using 6 il solution of GOD with BSA and 3 pi of glutaraldehyde (5%). The results of the studies related to the optimization of the composition of the enzyme layer were given elsewhere in detail (7.. We used these laminates with die Rank electrode described above, and measured the electrode response of the glucose in buffer solutions (5 ml) containing different amounts of glucose (up to 100 mM). 

A three-enzyme electrode system, such as needed for creatinine measurement, poses a more difficult enzyme-immobilisation problem, in that different enzymes have different immobilisation requirements and their microenvironmental interrelationships need to be optimised. For one creatine sensor, the requisite creatine amidinohydrolase and sarcosine oxidase were immobihsed in polyurethane pre-polymer and PEG-hnked creatinine amidohydrolase was attached via diisocyanate pre-polymer to create a polyurethane adduct [14]. The likelihood of enzyme inactivation with chemical immobih-sation is high, but provided an enzyme preparation survives this, long-term stability is feasible. In the case of these three particular enzymes, a loss of activity resulted from silver ions diffusing from the reference electrode the material solution was to protect the enzyme layer with a diffusion-resisting cellulose acetate membrane. 

A supramolecular complexation between avidin and biotin-labeled enzyme results in the formation of enzyme multilayers composed of avidin and enzyme monolayers, in which each monolayer is connected through avidin-biotin complexation with each other. The thickness of the multilayers can be precisely controlled by regulating the deposition number (the thickness of each avidin plus enzyme double layer is approximately 10 nm). The enzyme multilayers are useful in preparing high... 

At present, the binary water-soluble preparation of heparin and proteolytic enzymes is being applied for the treatment of thromboses. For instance, injection into the bloodstream of heparin-plasmin complex or a heparin-plasmin-streptokinase preparation leads to the total dissolution of the thrombus, while if introduced separately, heparin and streptokinase do not display the lytic action at all, and plasmin, alone or together with streptokinase, dissolves the thrombus only partially 132>. The treatment of acute thrombophlebitis with trypsin resulted in a full dissolution of the thrombus and in an increase of antithrombin III in the blood 133). Administration of trypsin together with heparin has an effect similar in efficiency to the action of the heparin-plasmin complex 134>. The use of a mix of heparin and urokinase for improving tbrom-boresistance of polymeric materials was also described 13S). These substances were immobilized by preliminary coating of the surface of a polymer with a graphite layer and subsequent adsorption of heparin and the enzyme. 

Cut a fresh, medium-sized potato (precooled for 24 hr at 1 to 5°C you need not peel the potato, but it should be washed to remove dirt and dust) into half-inch cubes. Blend 150 g of these cubes, added over a 30-sec period, with 150 ml of F120 for 2 min in a blender. Then quickly pour the resultant slurry onto a Buchner funnel lined with two to four layers of cheesecloth, and filter with vacuum, collecting the filtrate in the filter flask you prepared in step 2. Wash the crude pulp with 50 ml of H20 to ensure thorough enzyme extraction that is, add the water to the pulp, stir the mixture, and pass the mixture through the filter as before. Failure to complete these operations within 2 min of blending may result in loss of enzyme activity. Adjust the extract to a volume of 250 ml with... 

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