Protease-specificity of Kunitz inhibitor domain of Alzheimer's disease amyloid protein precursor |
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Authors: | H Kido A Fukutomi J Schilling Y Wang B Cordell N Katunuma |
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Institution: | Division of Enzyme Chemistry, University of Tokushima, Japan. |
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Abstract: | The putative inhibitor domain of Alzheimer's disease amyloid protein precursor was purified from E. coli containing a synthetic gene encoding the Kunitz domain. The purified protein (A4 inhibitor) inhibited the activity of trypsin, forming a 1:1 molar complex with the enzyme. It also strongly inhibited plasmin (Ki = 7.5 x 10(-11) M) from human serum and tryptase (Ki = 2.2 x 10(-10) M) from rat mast cells (tryptase M). In addition, it inhibited rat pancreatic trypsin, alpha-chymotrypsin and kallikrein and human serum kallikrein, but did not inhibit rat chymase, pancreatic elastase, alpha-thrombin, urokinase, papain or cathepsin B. |
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