Methods for determining squalene synthase activity

A method for determining squalene synthase activity, comprising:

• a) contacting NADPH, FPP and a magnesium ion cofactor with a squalene synthase;
• b) exposing the reaction mixture to UV light;
• and
• c) detecting the emitted fluorescent light,
• wherein the decrease in the amount of fluorescent light is correlated to the amount of NADPH consumed in the synthesis of squalene, and
• wherein the amount of squalene is correlated to the amount of NADPH consumed.

A method for identifying a test compound as an inhibitor or promoter of squalene synthase, comprising:

• a) contacting NADPH, FPP and a magnesium ion cofactor with a squalene synthase in the presence and in the absence of a test compound;
• b) exposing the reaction mixture to UV light;
• and
• c) detecting the emitted fluorescent light over time,
• wherein the decrease in the amount of fluorescent light over time is correlated to the amount of NADPH consumed in the synthesis of squalene, and
• wherein the amount of squalene produced over time is correlated to the amount of NADPH consumed, and
• wherein an increase in the amount of fluorescent light emission over time in the presence of the test compound indicates that the test compound is a squalene synthase inhibitor, and
• wherein a decrease in the amount of fluorescent light emission over time in the presence of the test compound indicates that the test compound is a squalene synthase promoter.

A method for identifying compounds capable of selectively promoting or inhibiting plant, fungal and/or animal squalene synthase activity, comprising:

• a) combining FPP, NADPH, a magnesium ion cofactor and a plant squalene synthase to form a reaction mixture under conditions suitable for the production of squalene in the presence and absence of a test compound;
• b) subjecting the reaction mixture to UV light and detecting fluorescent light emission over time,
• c) determining the activity of the compound to promote or inhibit squalene synthase based on the fluorescent light emission over time,
• d) repeating steps a-c using a fungal or animal squalene synthase, and
• f) identifying compounds that selectively inhibit plant, fungal or animal squalene synthase.