However, efforts to demonstrate such enzymes in coconut or Cuphea, which could explain their abundant production of medium-chain fatty acids, have met with little success. achieved the breakthrough finding that validated this hypothesis. They examined the California bay tree, which produces over 75% decanoic and lauric acids in its seed TAG. A very active 12:0-ACP thioesterase was found, which could be separated from the ubiquitous 18:1-ACP thioesterase. Thus, California bay clearly has two acyl-ACP thioesterases with different substrate specificity; subsequent studies of several other oilseed species have revealed similar medium-chain thioesterases.