| Popis: |
Kynurenic acid (KYNA), a normal component of the mammalian brain, has recently gained attention as a broad spectrum antagonist of ionotropic excitatory amino acid receptors (Stone et al., 1993). While in mammalian peripheral organs, KYNA is biosynthesized from L-kynurenine by several rather unspecific aminotransferases (Noguchi et al., 1975, Okuno et al, 1980), it appears that a single enzyme, kynurenine aminotransferase (KAT), is responsible for KYNA synthesis in the rat brain (Okuno et al., 1991a). In the human brain, on the other hand, two enzymes (KAT I and KAT II) have been characterized (Okuno et al., 1991b). These two KATs have distinct catalytic characteristics and can be physically separated by conventional techniques. |
