The enzyme shown to be at least partially responsible for this defluorination (after it has been converted into (2S, 4R)-4-[18F]fluoroglutamate) is alanine aminotransferase which, in a stroke of unfortunate luck, processes and defluorinates the compound 5.6 times more efficiently than its non-fluorinated natural counterpart [32]. Here, GPT is linked to stroke disorder.