Rossier J
Biochem J. 1977 Aug 1;165(2):321-6. doi: 10.1042/bj1650321.
Choline acetyltransferase has the same affinity for acetyl-CoA, propionyl-CoA and butyryl-CoA (Km=1.4 micron). Choline acetyltransferase may use the two latter compounds as substrate, but the longer the acyl chain the lower will be Vmax. CoA is an inhibitor (Ki=1.8 micron). The position of the 3'-phosphate is of primary importance. Desphospho-CoA is a weak inhibitor (Ki=500 micron). 5'-AMP is already an inhibitor (Ki=2500 micron). Phosphopantetheine is not an inhibitor. Dextran Blue is a potent inhibitor (Ki=0.05 micron). Choline acetyltransferase binds to hydrophobic affinity columns. Because of its affinity for nucleotides, affinity for Dextran Blue and hydrophobicity, it is proposed that it contains the 'nucleotide fold', which is a common structural domain present in several enzymes binding nucleotides.
胆碱乙酰转移酶对乙酰辅酶A、丙酰辅酶A和丁酰辅酶A具有相同的亲和力(米氏常数Km = 1.4微米)。胆碱乙酰转移酶可能将后两种化合物用作底物,但酰基链越长,最大反应速度(Vmax)就越低。辅酶A是一种抑制剂(抑制常数Ki = 1.8微米)。3'-磷酸的位置至关重要。去磷酸辅酶A是一种弱抑制剂(Ki = 500微米)。5'-腺苷酸已经是一种抑制剂(Ki = 2500微米)。磷酸泛酰巯基乙胺不是抑制剂。葡聚糖蓝是一种强效抑制剂(Ki = 0.05微米)。胆碱乙酰转移酶能与疏水亲和柱结合。由于它对核苷酸有亲和力、对葡聚糖蓝有亲和力且具有疏水性,因此有人提出它含有“核苷酸折叠”结构,这是存在于几种结合核苷酸的酶中的一种常见结构域。