AMINE OXIDASE ACTIVITIES IN RAT BREAST-CANCER INDUCED EXPERIMENTALLY WITH 7,12-DIMETHYLBENZ(ALPHA)ANTHRACENE
AMINE OXIDASE ACTIVITIES IN RAT BREAST-CANCER INDUCED EXPERIMENTALLY WITH 7,12-DIMETHYLBENZ(ALPHA)ANTHRACENE
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DOI：
10.1016/0006-2952(91)90712-e
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发表时间：
1991-07-05
影响因子：
5.8
通讯作者：
UNZETA, M
中科院分区：
文献类型：
--
作者：
LIZCANO, JM;ESCRICH, E;UNZETA, M
本文研究了7，12-二甲基苯蒽（DMBA）诱发的大鼠乳腺实体瘤中单胺氧化酶（MAO）和氨基脲敏感胺氧化酶（SSAO）的活性和分布。根据病理解剖学标准将乳腺肿瘤分为良性纤维腺瘤（FAD）、恶性腺癌（ADC）和浸润性腺癌（I-ADC）。总MAO活性（15%）和SSAO活性（85%）的比例不随恶性程度而变化。然而，恶性程度的增加与MAO-A活性的增加和MAO-B和SSAO活性的减少有关。动力学常数分别计算SSAO和每一个MAO形式，使用特定的基板。K（m）值随恶性程度无明显变化，但MAO-A的V（max）值随恶性程度增加而增加，SSAO和MAO-B的V（max）值随恶性程度增加而减少。SSAO活性对蛋白质浓度的依赖性表明，在更恶性的肿瘤提取物中存在内源性可逆抑制物质。这种抑制剂与微粒体组分相关，并且不能通过透析去除。它也存在于洗涤剂溶解的提取物中，这表明这种现象可能是由于酶本身产生的非活性物种的关联。
The activities and distribution of monoamine oxidase (MAO) and semicarbazide-sensitive amine oxidase (SSAO) in solid breast tumour induced in the rat by treatment with 7,12-dimethylbenz(alpha)anthracene (DMBA) were studied. The mammary tumours were classified according to anatomopathological criteria into: the benign fibroadenoma (FAD) and the malignant adenocarcinoma (ADC) and infiltrant adenocarcinoma (I-ADC). The proportions of total MAO (15%) and SSAO activities (85%) did not change with malignancy. However, an increasing degree of malignancy was associated with an increase in MAO-A activity and a decrease in MAO-B and SSAO activities. Kinetic constants were calculated for SSAO and for each MAO form separately, using specific substrates. The K(m) values did not change significantly with the degree of malignancy, but V(max) values for MAO-A increased whereas V(max) for SSAO and MAO-B diminished with malignancy. The dependence of SSAO activity on protein concentration indicated the presence of endogenous reversible inhibitory material in extracts from the more malign tumours. This inhibitor was associated with the microsomal fraction and was not removed by dialysis. It was also present in detergent-solubilized extracts, suggesting that the phenomenon might be due to an association of the enzyme itself producing an inactive species.