Singer A L, Sherwin R P, Dunn A S, Appleman M M
Cancer Res. 1976 Jan;36(1):60-6.
Cyclic nucleotide phosphodiesterase activity was studied in 33 malignant neoplastic, 2 benign neoplastic, and 18 nonneoplastic human mammary tissues. Enzyme activity, using both cyclic adenosine 3':5'-monophosphate and cyclic guanosine 3':5'-monosphosphate as substrates, was measured in whole homogenates over a concentration range of 1 to 100 muM. Specific activity was calculated at substrate concentrations of 1 muM (low KM enzyme activity) and 100 muM (high KM activity). Diethylaminoethyl cellulose chromatography was used to separate the different enzyme species. The malignant neoplastic tissues had higher levels of both low-KM cyclic adenosine 3':5'-monophosphate and low-KM cyclic guanosine 3':5'-monophosphate phosphodiesterases. Further, the mean value of the ratio of low-km cyclic adenosine 3':5'-monophosphate to low-KM cyclic guanosine 3':5'-monophosphate activity was higher for the cancer tissues than for the nonneoplastic tissues. Diethylaminoethyl cellulose chromatography indicated the presence of three enzymes in both neoplastic and nonneoplastic mammary tissue. The kinetic as well as regulatory properties of the separated enzymes indicated that they are distinct enzyme activities. The phosphodiesterase properties were similar for neoplastic and nonneoplastic tissues and resembled those described previously in many other mammalian tissues. While both neoplastic and nonneoplastic tissues had detectable levels of the protein activator for phosphodiesterase, the cancer tissues appeared to have a higher level.
在33例恶性肿瘤、2例良性肿瘤和18例非肿瘤性人类乳腺组织中研究了环核苷酸磷酸二酯酶活性。以环腺苷3':5'-单磷酸和环鸟苷3':5'-单磷酸作为底物，在1至100μM的浓度范围内测定全匀浆中的酶活性。在底物浓度为1μM（低Km酶活性）和100μM（高Km活性）时计算比活性。使用二乙氨基乙基纤维素色谱法分离不同的酶种类。恶性肿瘤组织中低Km环腺苷3':5'-单磷酸和低Km环鸟苷3':5'-单磷酸磷酸二酯酶的水平均较高。此外，癌组织中低Km环腺苷3':5'-单磷酸与低Km环鸟苷3':5'-单磷酸活性之比的平均值高于非肿瘤组织。二乙氨基乙基纤维素色谱法表明，肿瘤性和非肿瘤性乳腺组织中均存在三种酶。分离出的酶的动力学和调节特性表明它们是不同的酶活性。肿瘤性和非肿瘤性组织的磷酸二酯酶特性相似，与先前在许多其他哺乳动物组织中描述的特性相似。虽然肿瘤性和非肿瘤性组织中磷酸二酯酶的蛋白质激活剂水平均可检测到，但癌组织中的水平似乎更高。
