Table 3.

Major biochemical differences of four KATs

	Optimal pH range	Recommended assay pH	Recommended co-substrate	Specific inhibitors of KAT activity	Unique substrates
KAT I	7.5–10	9–10	Glyoxylate	Tryptophan
				3-indolepropionic acid
				dl-indole-3-lactic acid
KAT II	7–9	7–8	α-ketoglutarate	(S)-4-ethylsulfonylbenzoylalanine (rat KAT II)	Aminoadipate
KAT III	9–10 (mouse)	9–10 (mouse)	Glyoxylate	Methionine (mouse)
KAT IV	7–9 (mouse)	7–8 (mouse)	α-ketoglutarate	Aspartate (mouse)	Aspartate (mouse)

Unless specified, the listed parameters are for human enzymes