N-Methyl-d-aspartate (NMDA), which is a selective agonist for the NMDA receptor, has recently been shown to be present in various biological tissues. In mammals, the activity of d-aspartate N-methyltransferase (DDNMT), which produces NMDA from d-aspartate, has been detected only in homogenates prepared from rat tissues. Moreover, the enzymatic properties of DDNMT have been poorly studied and its molecular entity has not yet been identified. In this report, we show for the first time that the activity of DDNMT is present in mouse tissues and succeed in obtaining a partially purified enzyme preparation from a mouse tissue homogenate with a purification fold of 1900 or more, and have characterized the enzymatic activity of this preparation. The results indicate that DDNMT, which is highly specific for d-aspartate and is S-adenosyl-l-methionine-dependent, is a novel enzyme that clearly differs from the known methylamine-glutamate N-methyltransferase (EC 2.1.1.21) and glycine N-methyltransferase (EC 2.1.1.20).

ñ -甲基- ð天冬氨酸（NMDA），其是用于NMDA受体的选择性激动剂，最近已被证明存在于各种生物组织。在哺乳动物中，活性d天冬氨酸Ñ -methyltransferase（DDNMT），其从产生NMDA d-天冬氨酸，仅在从大鼠组织制备的匀浆中被检测到。此外，对DDNMT的酶学性质的研究很少，其分子实体尚未确定。在本报告中，我们首次展示了DDNMT的活性存在于小鼠组织中，并成功地从匀浆度为1900或更高的小鼠组织匀浆中获得了部分纯化的酶制剂，并表征了DDNMT的酶活性。这个准备。结果表明，DDNMT对d-天门冬氨酸具有高度特异性，并且是S-腺苷-1-蛋氨酸依赖性的，是一种新型酶，明显不同于已知的甲胺-谷氨酸N-甲基转移酶（EC 2.1.1.21）和甘氨酸N-甲基转移酶（EC 2.1.1.20）。