Propenylcysteine sulfoxide

Several questions arise—why is the first compound observed as a product of the enzymatic reaction a dimer, except in onion 21), although a monomeric product is expected Why are the 1-propenyl disulfides found only in small quantities although S-l-propenylcysteine sulfoxide is the principal precursor present Why do onions make the eyes water when garlic does not Why is a monomeric product found only in onions although the enzyme from all sources acts similarly on all types of substrate ... 

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