Compounds and methods of use thereof for assaying lysophospholipase D activity

A method for assaying the lysophospholipase D (LysoPLD) activity of autotoxin (ATX) comprising the steps of:

• a) obtaining a solution having ATX present;
• b) adding a LysoPLD substrate comprising a lysophospholipid derivative labeled with a fluorescent group and a quencher group to said solution containing ATX;
• and
• c) determining if LysoPLD activity is present in said solution by measuring the change in the fluorescent signal in said solution that is generated by the cleavage of said lysophospholipid derivative represented by the formula:
• wherein A represents O or S;
• B represents H, Na+, K+, Li+or an alkyl group having 1-20 carbon atoms;
• E represents O, CH2, CHF or CF2;
• G represents H, OH, F, O-acyl or O-alkyl having 1-20 carbon atoms;
• K1 and K2 each represent H, F, alkyl having 1 to 20 carbon atoms, OH or CO2H;W is C(O), NH(CH2CH2O)qC(O) or (NHC(O)(CH2)n)pC(O), wherein q is an integer from 1 to 33;
• n is an integer from 1 to 12;
• and p is an integer from 1 to 20;
• X represents NH;
• Y represents O, S or NH;
• Z is C(O)(CH2)n(C)NH, (CH2CH2O)qC(O)NH or (CH2) nNH wherein n is an integer from 1 to 33;
• and R1 and R2 are a fluorescent group or a quencher, respectively.