Van Der Ouderaa F J, Buytenhek M, Nugteren D H, Van Dorp D A
Eur J Biochem. 1980 Aug;109(1):1-8. doi: 10.1111/j.1432-1033.1980.tb04760.x.
Incubation of purified prostaglandin endoperoxide synthetase from sheep vesicular glands with aspirin results in a covalent binding of the acetyl group of acetylsalicylic acid to the protein. During this acetylation, the cyclooxygenase activity is lost, but not the peroxidase activity. The reaction is completed when almost one acetyl group is bound per polypeptide chain (Mr = 68 000). After proteolysis of [3H]acetyl-protein with pronase, radioactive N-acetylserine was obtained. Originally, however, the hydroxyl group of an internal serine residue in the chain is acetylated. The formation of N-acetylserine can be explained by a rapid O leads to N acetyl shift as soon as the NH2 group of serine is liberated. A radioactive dipeptide was isolated from a thermolysin digest of the [3H]acetyl-enzyme containing phenylalanine and serine, phenylalanine being its N-terminal amino acid. Automatic Edman degradation of native and acetylated enzyme showed that only one polypeptide sequence was present: Ala-Asp-Pro-Gly-Ala-Pro-Ala-Pro-Val-Asn-Pro-X-X-Tyr-. The N-terminal sequence has an apolar character.
将绵羊精囊的纯化前列腺素内过氧化物合成酶与阿司匹林一起温育，会导致乙酰水杨酸的乙酰基与该蛋白质发生共价结合。在这种乙酰化过程中，环氧化酶活性丧失，但过氧化物酶活性未丧失。当每条多肽链（Mr = 68 000）结合几乎一个乙酰基时，反应完成。用链霉蛋白酶对[3H]乙酰化蛋白质进行蛋白水解后，得到了放射性N - 乙酰丝氨酸。然而，最初链中一个内部丝氨酸残基的羟基被乙酰化。一旦丝氨酸的NH2基团被释放，N - 乙酰丝氨酸的形成可以通过快速的O→N乙酰基转移来解释。从含有苯丙氨酸和丝氨酸的[3H]乙酰化酶的嗜热菌蛋白酶消化物中分离出一种放射性二肽，苯丙氨酸是其N端氨基酸。天然酶和乙酰化酶的自动埃德曼降解表明只存在一种多肽序列：Ala - Asp - Pro - Gly - Ala - Pro - Ala - Pro - Val - Asn - Pro - X - X - Tyr - 。N端序列具有非极性特征。
