Azocasein method

EFE is immobilized in a Korean type total artificial heart valve by photoreaction polyallylamine is used as a photoreactive linker [86-88]. The proteolytic activity of the treated valves is three times higher than that of untreated valves using the azocasein method. These data show that an EFE-treated polyurethane valve leads to decreasing thrombus formation in vivo and that their biocompatibility is therefore greater than that of untreated valve. It is expected that EFE could be applied as a novel accessory in the artificial organs implanted into human body. 

Azocasein Method Azocasein is a modified protein bearing a chromogenic group which is released in solution upon digestion. At the end of the reaction, carried out under... 

For activity assays, proteinase solutions were made fresh daily (10 mg freeze-dried solids in 1 ml pH 10.0 phosphate buffer, 0.1 M). Two ml of the proteinase, 0.5 ml of substrate (azocasein or other proteins in pH 10 buffer), 0.3 ml of 0.1% EDTA, and deionized water were made up to a volume of 3.5 ml. Reaction tubes were incubated in a 40°C water bath for 1 hr, then the reaction was stopped by addition of 1 ml 5% TCA. After removal of the precipitated proteins by centrifugation, absorbance was read at 366 nm (for azocasein) or by the Lowry method (15) for other... 

The protease activity was determined by the method described by Chamey and Tomarelli [18] that is based on the formation of colored protein-derived compounds hy the digestion of an azocasein solution with the proteolitic enzymes present in the enzymatic extract. 

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