Yeast assay to identify inhibitors of dibasic amino acid processing endoproteases

A method to identify an inhibitory compound that reduces the infectivity of an infectious agent, comprising:

• (a) contacting a yeast strain containing a precursor protein having a dibasic amino acid processing site with a putative inhibitory compound under conditions in which, in the absence of the compound, said yeast strain is capable of effecting cleavage of said precursor protein into cleavage products;
• and
• (b) assaying for production of said cleavage products, wherein production of a reduced amount of said cleavage products in the presence of said putative inhibitory compound compared to in the absence of said putative inhibitory compound indicates that said compound is able to inhibit proteolytic cleavage by said endoprotease, the ability of said compound to inhibit said cleavage being indicative of the ability of said compound to reduce the spread of said infectious agent in an organism infected by said infectious agent.

A test kit to identify a compound capable of inhibiting a dibasic amino acid processing endoprotease, said kit comprising a yeast strain capable of producing a precursor protein selected from the group consisting of yeast and heterologous precursor proteins, said yeast strain being capable of effecting cleavage of said precursor protein into cleavage products, and a means for determining the extent of cleavage by said yeast strain in the presence of a putative inhibitory compound, said means for determining comprising means for assaying for production of said cleavage products, wherein production of a reduced amount of said cleavage products in the presence of said putative inhibitory compound compared to in the absence of said putative inhibitory compound indicates that said compound is able to inhibit proteolytic cleavage by said endoprotease.

A method to identify a compound capable of inhibiting an animal or plant dibasic amino acid processing endoprotease, said method comprising:

• (a) contacting a putative inhibitory compound with a secreted soluble dibasic amino acid processing endoprotease protein fragment in the presence of a precursor protein having a dibasic amino acid processing site under conditions in which, in the absence of said compound, said protein fragment is capable of effecting cleavage of said precursor protein into cleavage products;
• and
• (b) assaying for production of said cleavage products, wherein production of a reduced amount of said cleavage products in the presence of said putative inhibitory compound compared to in the absence of said putative inhibitory compound indicates that said compound is able to inhibit proteolytic cleavage by said endoprotease.