Oakes M G, Davis T P
Department of Pharmacology, University of Arizona, College of Medicine, Tucson 85724.
Brain Res Dev Brain Res. 1994 Jul 15;80(1-2):127-36. doi: 10.1016/0165-3806(94)90096-5.
We quantitated the level of activity of several peptidases to determine if enzymes involved in the post-translational processing and metabolism of peptides are detectable and are altered developmentally in specific regions of the rat brain. Carboxypeptidase H (EC 3.4.17.10), a processing enzyme, located in chromaffin secretory granules was expressed at high levels on postnatal day 0 (P 0, birth) in hypothalamus, cortex and cerebellum (3.48, 4.98, 4.29 pmol/mg/min, respectively). An increase of activity occurred from P 0 to P 7 in both hypothalamus and cortex (7.68, 6.94) with a decrease shown in cerebellum (3.89). After P 7, activity increased by P 90 (adult) in the hypothalamus (7.65), decreased to birth levels in the cortex (4.79) and decreased below birth levels in the cerebellum (2.76). This regional pattern of carboxypeptidase H activity may signify its involvement throughout the life of the rat in the synthesis of specific regional neuropeptides important in development. Enzyme activity for the degradative enzymes, neutral endopeptidase (EC 3.4.24.11) and metallo endopeptidase (EC 3.4.24.15) did not present the same developmental pattern as seen with the processing enzyme. Neutral endopeptidase activity doubled in the hypothalamus from P 0 to P 7 (3080 pmol/mg/min) and remained constant throughout the maturation of the animal. In the cortex, activity increased significantly from P 0 to P 30 (1171) and remained at that level to P 90. In the cerebellum, activity decreased from P 0 to P 30 (320) and remained at that level to P 90 (304). At birth, metallo endopeptidase activity was highest in cortex (2702 pmol/mg/min), intermediate in hypothalamus (1658) and lowest in cerebellum (1410).(ABSTRACT TRUNCATED AT 250 WORDS)
我们对几种肽酶的活性水平进行了定量，以确定参与肽的翻译后加工和代谢的酶是否可检测到，以及在大鼠脑的特定区域其活性是否会随发育而改变。羧肽酶H（EC 3.4.17.10）是一种加工酶，位于嗜铬分泌颗粒中，在出生后第0天（P0，出生时）在下丘脑、皮层和小脑中高水平表达（分别为3.48、4.98、4.29 pmol/mg/分钟）。从P0到P7，下丘脑和皮层的活性均增加（分别为7.68、6.94），而小脑的活性降低（3.89）。P7之后，下丘脑的活性在P90（成年）时增加（7.65），皮层的活性降至出生时水平（4.79），小脑的活性降至出生水平以下（2.76）。羧肽酶H活性的这种区域模式可能表明其在大鼠整个生命过程中参与了对发育过程中重要的特定区域神经肽的合成。降解酶中性内肽酶（EC 3.4.24.11）和金属内肽酶（EC 3.4.24.15）的酶活性呈现出与加工酶不同的发育模式。中性内肽酶活性在下丘脑中从P0到P7翻倍（3080 pmol/mg/分钟），并在动物成熟过程中保持恒定。在皮层中，活性从P0到P30显著增加（1171），并在P90时保持在该水平。在小脑中，活性从P0到P30降低（320），并在P90时保持在该水平（304）。出生时，金属内肽酶活性在皮层中最高（2702 pmol/mg/分钟），在下丘脑中中等（1658），在小脑中最低（1410）。（摘要截选至250字）
