Dumler I L, Garnovskaia M N, Artem'ev N O, Etingof R N
Biokhimiia. 1984 Oct;49(10):1727-32.
Precipitating monospecific antibodies against purified bovine retinal rod outer segment phosphodiesterase (EC 3.1.4.17) were obtained from rabbit blood serum. These antibodies do not form precipitating complexes with phosphodiesterase isolated from rat or ox brain tissues or from the heart, lung, liver, kidney, testes and uterus of the rat. The antibodies inhibit the activity of retinal rod outer segment phosphodiesterase or that of rat brain, liver, heart and uterus enzyme (despite the lack of precipitation) but have no effect on the phosphodiesterase activity of preparations obtained from rat lungs, kidney or testes. The same effect on the phosphodiesterase activity of all these tissues is exerted by monovalent fragments of the antibodies. Using partially purified preparations of phosphodiesterase from retinal rod outer segments and brain of the ox and from human myometrium, the mechanisms of inhibition of the enzyme catalytic activity by the antibodies was studied. In the presence of the antibodies, the Km and V values appeared to be different, depending on the preparation. It was assumed that a certain site in the phosphodiesterase molecule is characterized by great structural rigidity. Taking into account the shifts in the Km values induced by the antibodies, the differences in the localization of the antigenic determinant in relation to the enzyme active center are discussed.
针对纯化的牛视网膜杆状体外段磷酸二酯酶（EC 3.1.4.17）沉淀的单特异性抗体是从兔血清中获得的。这些抗体不会与从大鼠或牛脑组织或大鼠的心脏、肺、肝脏、肾脏、睾丸和子宫中分离出的磷酸二酯酶形成沉淀复合物。这些抗体抑制视网膜杆状体外段磷酸二酯酶或大鼠脑、肝脏、心脏和子宫酶的活性（尽管没有沉淀），但对从大鼠肺、肾脏或睾丸中获得的制剂的磷酸二酯酶活性没有影响。抗体的单价片段对所有这些组织的磷酸二酯酶活性具有相同的作用。使用从牛视网膜杆状体外部段和脑以及人子宫肌层中部分纯化的磷酸二酯酶制剂，研究了抗体抑制该酶催化活性的机制。在存在抗体的情况下，Km和V值似乎有所不同，这取决于制剂。据推测，磷酸二酯酶分子中的某个位点具有很大的结构刚性。考虑到抗体诱导的Km值变化，讨论了抗原决定簇相对于酶活性中心定位的差异。
