In enzymology, a cyclopropane-fatty-acyl-phospholipid synthase () is an enzyme that catalyzes the chemical reaction
Thus, the two substrates of this enzyme are S-adenosyl methionine and phospholipid olefinic fatty acid, whereas its two products are S-adenosylhomocysteine and phospholipid cyclopropane fatty acid.
This enzyme belongs to the family of transferases, specifically those transferring one-carbon group methyltransferases. The systematic name of this enzyme class is S-adenosyl-<small>L</small>-methionine:unsaturated-phospholipid methyltransferase (cyclizing). Other names in common use include cyclopropane synthetase, unsaturated-phospholipid methyltransferase, cyclopropane synthase, cyclopropane fatty acid synthase, cyclopropane fatty acid synthetase, and CFA synthase.
As of late 2007, 6 structures have been solved for this class of enzymes, with PDB accession codes , , , , , and .