And so what happens is now we have histidine 320 that donates its H ion onto this oxygen of the carbonyl group of the oxalo acetate. And this basically weakens the pi bond, it forms a carbocation intermediate and that converts this poor electrophile into a much better electrophile. And so now, because this is a very good electrophile, this pi bond of this ENL can act as a nucleophile and attack the carbon nucleophilically to form that connection between this acetyl group and this citrate molecule. And so, in the next step, we are able to actually form that citral Co enzyme A. And once we form the citrus coenzyme A, that induces even more conformational changes that completely seal off these active sites. And by sealing off the active side, that basically prevents different types of competing reactions from actually taking place.