Khoo H G, Wong K P
Department of Biochemistry, Faculty of Medicine, National University of Singapore, Kent Ridge.
Insect Biochem Mol Biol. 1994 May;24(5):445-51. doi: 10.1016/0965-1748(94)90039-6.
Acetyl CoA synthetase (ACS; EC 6.2.1.1) was studied in the mosquito, Aedes togoi, by a novel assay which coupled the acetyl-CoA generated to p-aminosalicylic acid (ASA). The N-acetylated product was determined by an HPLC-fluorimetric procedure. High ACS activity was observed in the newly-pupated pupae of both sexes and in the adult male mosquito whose activity was five times that of the female. Acetyl CoA-dependent N-acetyltransferase (NAT; EC 2.3.1.5) activity toward serotonin (5HT) was also studied using HPLC-electrochemical detection (HPLC-ECD). A progressive increase in the 5HT-NAT activity was observed from the fourth-instar larvae to the adult mosquito with the latter showing 6-fold higher activity in the head compared to the abdomen-thorax region. Kinetic studies on the pupal enzyme extracts showed that the apparent Km values for 5HT and acetyl CoA were 63 and 66 microM respectively. Tryptamine inhibited 5HT-NAT non-competitively with a Ki value of 8 microM.
通过一种将生成的乙酰辅酶A与对氨基水杨酸（ASA）偶联的新型测定法，对致倦库蚊中的乙酰辅酶A合成酶（ACS；EC 6.2.1.1）进行了研究。通过高效液相色谱 - 荧光法测定N - 乙酰化产物。在新羽化的雌雄蛹以及成年雄蚊中观察到高ACS活性，成年雄蚊的活性是雌蚊的五倍。还使用高效液相色谱 - 电化学检测法（HPLC - ECD）研究了乙酰辅酶A依赖性N - 乙酰转移酶（NAT；EC 2.3.1.5）对血清素（5HT）的活性。从四龄幼虫到成年蚊，观察到5HT - NAT活性逐渐增加，成年蚊头部的活性比腹部 - 胸部区域高6倍。对蛹酶提取物的动力学研究表明，5HT和乙酰辅酶A的表观Km值分别为63和66 microM。色胺以8 microM的Ki值非竞争性抑制5HT - NAT。
