Kapoor V, Thuruthyil S J, Human B
Faculty of Medicine, School of Physiology and Pharmacology, University of New South Wales, Kensington, Sydney, Australia.
Neuroreport. 1998 May 11;9(7):1431-4. doi: 10.1097/00001756-199805110-00033.
Kynurenine aminotransferase I (KAT-I), which also shows glutamine transaminase K (GTK) activity, catalyses the conversion of kynurenine to kynurenic acid, an endogenous glutamate antagonist. Both the GTK and KAT enzyme activities were found to be significantly reduced in kidney, brain and medulla oblongata homogenates of spontaneously hypertensive (SHR) compared to Wistar-Kyoto (WKY) rats. Enzyme activity stains on native gel separations of partially purified kidney homogenates was associated with two major bands of GTK (KAT-I)-activity in WKY and Wistar rats, KAT-Ia and KAT-Ib. SHR rats however showed only KAT-Ia activity. These findings suggest that the absence of KAT-Ib activity may result in a reduced ability to synthesise kynurenic acid in SHR rats, this may help to explain the enhanced sensitivity to glutamate seen in this strain.
犬尿氨酸转氨酶I（KAT-I），也表现出谷氨酰胺转氨酶K（GTK）活性，催化犬尿氨酸转化为犬尿酸，一种内源性谷氨酸拮抗剂。与Wistar-Kyoto（WKY）大鼠相比，自发性高血压（SHR）大鼠的肾脏、大脑和延髓匀浆中的GTK和KAT酶活性均显著降低。在WKY和Wistar大鼠部分纯化的肾脏匀浆的天然凝胶分离上进行酶活性染色，与GTK（KAT-I）活性的两条主要条带相关，即KAT-Ia和KAT-Ib。然而，SHR大鼠仅表现出KAT-Ia活性。这些发现表明，KAT-Ib活性的缺失可能导致SHR大鼠合成犬尿酸的能力降低，这可能有助于解释该品系对谷氨酸的敏感性增强。
