Bongiorno L, Marzano M, Marini M, Roda L G, Urbani A, Spagnoli G
Dipartimento di Medicina Sperimentale, Università degli Studi 'Tor Vergata', Roma, Italia.
Gerontology. 1999 Jan-Feb;45(1):10-6. doi: 10.1159/000022049.
The existence of age-associated alterations in immune functions and neuropeptides capable of modulating these functions prompted us to advance the hypothesis that the degradation of plasma neuropeptides, specifically opioid peptides, may be altered by aging.
To verify the possible existence of age-induced variations in neuropeptide hydrolysis in human plasma, using leucine enkephalin as the model substrate.
The hydrolysis of leucine enkephalin and the formation of its hydrolysis byproducts in the presence of plasma enzymes were studied by kinetic and chromatographic techniques in a group of elderly individuals and a control group.
The results obtained indicate that in elderly individuals the activity of enkephalin-degrading plasma enzymes is greater than in controls. ANOVA analysis of these data indicates that the dependency of the variation of hydrolysis upon the 2 age groups is statistically significant. Increased substrate hydrolysis, and a modified hydrolysis pattern, appear to be associated with increased activity of the enzymes involved, and with different distribution of the individual enzymes within each class, as well as with severely reduced activity of the low molecular weight plasma inhibitors.
The combination of the above-mentioned factors appears to define a characteristic hydrolysis pattern for elderly individuals which is different from that found in controls.
免疫功能存在与年龄相关的改变，且存在能够调节这些功能的神经肽，这促使我们提出一个假说，即血浆神经肽，特别是阿片肽的降解可能会因衰老而改变。
以亮氨酸脑啡肽为模型底物，验证人血浆中神经肽水解是否存在年龄诱导的变化。
采用动力学和色谱技术，在一组老年人和一个对照组中研究亮氨酸脑啡肽在血浆酶存在下的水解及其水解副产物的形成。
所得结果表明，老年人中降解脑啡肽的血浆酶活性高于对照组。对这些数据进行方差分析表明，水解变化对两个年龄组的依赖性具有统计学意义。底物水解增加以及水解模式改变，似乎与相关酶活性增加、各类别中个体酶的不同分布以及低分子量血浆抑制剂活性严重降低有关。
上述因素的组合似乎定义了老年人特有的水解模式，该模式与对照组不同。
