A reappraisal of the dog-heart infarct plasmalogen, its conception as a bis-phosphatidic acid and current recognition as an N-acyl phosphatidyl ethanolamine.

1. We have re-examined the lipids from myocardial infarcts of cat, dog, rabbit and man, mainly through TLC methods, and confirm the identity of cat and dog "infarct plasmalogen" as an N-acyl phosphatidyl ethanolamine (NAPE). This substance was not detected in infarcts of rabbit and man. 2. We have extended our observations on a similar phosphatide, as the plasmalogen form, naturally occurring in the brain and optic nerve of fish. 3. Supporting evidence for the NAPE identity was provided from non-plasmalogen forms isolated from peas and lentils. 4. NAPE in all of its forms was shown to be a reluctant substrate for the phospholipase A2 of snake venoms. 5. Co-chromatography problems involving NAPE, semi-lyso cardiolipin and bis-phosphatidic acid are documented and their relationship to the infarct phenomenon discussed.