| Phospholipase A2 is a member of the class of heat-stable, calcium-dependent enzymes catalyzing the hydrolysis of the 2-acyl bond of 3-n-phosphoglycerides. The enzyme has a molecular weight of 30,000 daltons. Phospholipase A2 is activated by Ca2+. It is inhibited by zinc, barium, and manganese ions. Activity values for phospholipase A preparations which are derived from titrimetric assay procedures can be quite dependent on source and type of lecithin, its preparation as a substrate emulsion, other components of the reaction mixture, and the method and instrumentation used. Activity: 200 units per mg dry weight A280 mg/ml: As Reported Unit Definition: 1 unit releases 1umole of acid from soybean lecithin per minute at 25C, pH 8.9 Activators: Calcium ion (Dennis 1973) Inhibitors: Zinc, barium and manganese ions (Uthe 1971). Also see Golec et al. (1992). Isoelectric Point: 4.55 and 4.40 for Aalpha and Abeta, respectively Extinction Coefficient: As Reported Storage and Stability: Lyophilized powder may be stored at 4C. Stable for 6 months after receipt at 4C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer. |
