Measurement of lp-pla2 activity

A method for measuring lipoprotein-associated phospholipase A2 (Lp-PLA2) activity in a sample containing Lp-PLA2,

• the method comprising the following steps (A) to (C):
• (A) converting platelet-activating factors (PAFs) represented by General Formula I below:
• wherein:
• R1 is a linear or branched, saturated or partially unsaturated higher hydrocarbon group;
• R2 is a linear lower alkyl group;
• and
• X is —C(O)—, —CH2— or —CH═CH—,
• into lyso-PAFs represented by General Formula II below:
• wherein R1 and X are defined as in General Formula I,
• by reacting the PAFs with the Lp-PLA2 in the sample;
• (B) hydrolyzing the lyso-PAFs produced in step (A) with an enzyme that is a protein according to any of (a) to (c) below to obtain hydrolysate:
• (a) a protein having an amino acid sequence represented by SEQ ID NO:
• 1 or 9,
• (b) a protein having an amino acid sequence represented by SEQ ID NO:
• 1 or 9 with one or more amino acids deleted, substituted or added therein, and having phospholipase D-like (PLD) activity against lyso-PAF but no PLD activity against PAF, or
• (c) a protein having an amino acid sequence having at least 90% sequence identity with an amino acid sequence represented by SEQ ID NO:
• 1 or 9, and having PLD activity against lyso-PAF but no PLD activity against PAF;
• and
• (C) measuring Lp-PLA2 activity in the sample by utilizing a quantitative change attributable to the hydrolysate obtained in step (B) as an indicator.

A kit for measuring lipoprotein-associated phospholipase A2 (Lp-PLA2) activity in a sample,

• the kit comprising:
• an enzyme that is a protein according to any of (a) to (c) below:
• (a) a protein having an amino acid sequence represented by SEQ ID NO:
• 1 or 9;
• (b) a protein having an amino acid sequence represented by SEQ ID NO:
• 1 or 9 with one or more amino acids deleted, substituted or added therein, and having phospholipase D-like (PLD) activity against lyso-platelet-activating factor (PAF) but no PLD activity against PAF;
• or
• (c) a protein having an amino acid sequence having at least 90% sequence identity with an amino acid sequence represented by SEQ ID NO:
• 1 or 9, and having PLD activity against lyso-PAF but no PLD activity against PAF;
• and
• PAFs represented by General Formula I below:
• wherein:
• R1 is a linear or branched, saturated or partially unsaturated higher hydrocarbon group;
• R2 is a linear lower alkyl group;
• and
• X is —C(O)—, —CH2— or —CH═CH—.