Discoverx Corporation

Peter Fung

Joseph L Horecka

Pyare L Khanna

Richard M Eglen

Improved methods of determining the intracellular state of a protein as well as modifications of the protein are provided by introducing a surrogate fusion protein comprising a member of an enzyme fragment complementation complex and a target protein. After exposing cells transformed with the surrogate fusion protein to a change in environment, e.g. a candidate drug, the cells are lysed, the lysate separated into fractions or bands, conveniently by gel electrophoresis and transferring the proteins by Western blot to a membrane. The bands on the membrane are developed using the other member of the enzyme fragment complementation complex and a substrate providing a detectable signal. The method is found to provide high sensitivity and the ability to observe modifications of the target protein.

Analysis of intracellular modifications

A protein reagent is provided for measuring protease enzyme activity in a sample. The protein reagent comprises two inhibition entities joined by a linker comprised of an indicator enzyme donor and an amino acid sequence susceptible to enzymatic cleavage. The protein reagent is substantially inhibited from binding to the cognate enzyme acceptor fragment, while the product of the enzymatic cleavage binds to the cognate enzyme acceptor fragment to form a functional indicator enzyme. The indicator enzyme activity is related to the protease enzyme activity of the sample.

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Sunnyvale, CA, United States of America

Peter Fung