天冬氨酸转氨甲酰酶 Aspartate carbamoyltransferase
（重定向自Aspartate carbamoyl transferase）
天冬氨酸转氨甲酰酶（英语：Aspartate carbamoyltransferase，EC2.1.3.2，简称为ATCase）是嘧啶核苷酸从头合成中很重要的一个酶，它催化的是天冬氨酸与氨甲酰磷酸生成氨甲酰天冬氨酸和磷酸的反应。
Aspartate carbamoyl transferase
中文百科
英语百科
Aspartate carbamoyltransferase 天冬氨酸转氨甲酰酶
（重定向自Aspartate carbamoyl transferase）
![Schematic diagram of ATCase structure, depicting spatial arrangement of green regulatory (R) and blue catalytic (C) subunits. Redrawn and modified from Ke et al., 1984.[5]](/uploads/202412/22/Aspartate_carbamoyltransferase_(ATCase)4135.jpg)
Aspartate carbamoyltransferase (also known as aspartate transcarbamoylase or ATCase) catalyzes the first step in the pyrimidine biosynthetic pathway (EC2.1.3.2).
In E. coli, the enzyme is a multi-subunit protein complex composed of 12 subunits (300 kDa in total). The composition of the subunits is C6R6, forming 2 trimers of catalytic subunits (34 kDa) and 3 dimers of regulatory subunits (17 kDa). The particular arrangement of catalytic and regulatory subunits in this enzyme affords the complex with strongly allosteric behaviour with respect to its substrates. The enzyme is an archetypal example of allosteric modulation of fine control of metabolic enzyme reactions.