Phospholipase Crotalus adamanteus venom

Saito, K. and Hanahan, D. J. (1962) A study of the purification and properties of the phospholipase A2 of Crotalus adamanteus venom, Biochemistry 1, 521-532. 

The venoms of poisonous snakes contain (among other things) a class of enzymes known as phospholipases, enzymes that cause the breakdown of phospholipids. For example, the venoms of the eastern diamondback rattlesnake (Crotalus adamanteus) and the Indian cobra Naja naja) both contain phospholipase Ag, which catalyzes the hydrolysis of fatty acids at the C-2 position of glyc-erophospholipids. 

A very satisfactory source of phospholipase A2 is the venom of the snake, Crotalus adamanteus (Eastern diamondback rattlesnake). This venom can be obtained in lyophilized form from commercial suppliers such as Miami Ser-pentarium (Miami, FL). Of importance, the lyophilization process does not alter the chemical, physical, or enzymatic characteristics of the original venom obtained from this snake. 

Partial (Semi) Synthesis. A blend of two methodologies can be used quite effectively to prepare mixed acid phosphatidylcholines, which are of prime importance in elucidating the structure of naturally occurring phospho-glyceride and phospholipase A2 activity. Perhaps the best scenario would be to illustrate the activity of the phospholipase A2 (from Crotalus adamanteus snake venom) toward a racemic phosphatidylcholine sample and toward individual sn-1 and sn-3 enantiomers. In each case the same result would be found, and so only the racemic mixture reaction is depicted in Figure 4-8. 

Phospholipase A2 Action. Incubation of phosphatidylserine with phospholipase A2 obtained from Crotalus adamanteus or Naja Naja snake venom will show that the serine-containing phosphoglyceride was smoothly and completely converted to a lysophosphatidylserine with liberation of 1 mol of fatty acid per mole of lipid P. The experimental procedure was the same as the one described before in this and in the previous chapter. The products of the reaction can be recovered by thin-layer chromatography on Whatman K6 plates in a solvent system of chloroform-acetone-methanol-acetic acid-water (4.5 2 1 1.3 0.5, v/v). 

Phospholipase A2 isolated from snake venom (Crotalus adamanteus) can attack cardiolipin with liberation of 2 mol of fatty acid per mol of phosphorus. This result argues for an sn-3 configuration for the native cardiolipin molecule. 

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