Abstract: The present invention provides a substantially pure phopholipase A.sub.2 protein isolated and purified from rabbit kidney cortex, having a molecular weight of 28 kDa as determined by SDS-PAGE, is calcium independent, is cytosolic, has a specific activity of approximately 1.2 .mu.mol/mg protein/minute and a pH optimum of approximately 7.5 and exhibits a preferential hydrolysis toward sn-2 fatty acid from diradylglycerophospholipids. Also provided are various methods of using, inhibiting or measuring.

Abstract: Leakage in a heat exchanger between two liquids which are in indirect heat exchange relationship is detected by marking one of the two liquids with a colorless chemical marker and detecting it in the second liquid by extraction and conversion to a colored material. The heat exchanger liquids are preferably organic liquids which are immiscible with water. The marker is detected in a heat exchanger liquid by extraction of the marker followed by chemical conversion of the marker to a colored material that can be detected visually. Aminoalkylnaphthalenes are suitable markers which can be extracted by an acidic aqueous solution and converted to a colored material by reaction with a diazotized aromatic amine. Phenylazoalkylphenol derivatives are also suitable markers which can be extracted and simultaneously converted to a colored material with a detection reagent which is comprised of water and a water-soluble amine.