Dixon J E, Woodford T A
Methods Enzymol. 1984;106:170-9. doi: 10.1016/0076-6879(84)06017-1.
The rat pituitary contains an enzyme which will acetylate certain ACTH fragments using acetyl coenzyme A. This acetyltransferase activity was found in all three lobes of the rat pituitary as well as in all other tissues examined. The rat pituitary enzyme appears to be largely particulate in nature. The enzyme sedimenting at 27,000 and 100,000 g had specific activities 4-10 times greater than the soluble fraction. The acetyltransferase activity was dependent on substrate concentration (ACTH) and pH, was linear with time, and was inactivated at 55 degrees. The enzyme would acetylate ACTH(1-24), (1-10), and ACTH(4-10), but would not use ACTH(2-10), (3-10), or ACTH(1-8) as substrates. The apparent Km values for the substrates were as follows: AcCoA, 2.2 microM, ACTH(1-24), 4.2 microM; ACTH(1-10), 96 microM; and ACTH(4-10), 37 microM.
大鼠垂体含有一种酶，该酶可利用乙酰辅酶A使某些促肾上腺皮质激素（ACTH）片段乙酰化。在大鼠垂体的所有三个叶以及所检查的所有其他组织中均发现了这种乙酰转移酶活性。大鼠垂体酶在本质上似乎主要是颗粒性的。在27,000和100,000 g下沉淀的酶的比活性比可溶部分高4至10倍。乙酰转移酶活性取决于底物浓度（ACTH）和pH，随时间呈线性关系，并且在55摄氏度时失活。该酶可使ACTH（1 - 24）、（1 - 10）和ACTH（4 - 10）乙酰化，但不会将ACTH（2 - 10）、（3 - 10）或ACTH（1 - 8）用作底物。底物的表观Km值如下：乙酰辅酶A为2.2微摩尔，ACTH（1 - 24）为4.2微摩尔；ACTH（1 - 10）为96微摩尔；ACTH（4 - 10）为37微摩尔。
