Llorens C, Malfroy B, Schwartz J C, Gacel G, Roques B P, Roy J, Morgat J L, Javoy-Agid F, Agid Y
J Neurochem. 1982 Oct;39(4):1081-9. doi: 10.1111/j.1471-4159.1982.tb11500.x.
The compound [3H]Tyr1,D-Ala2,Leu-OH5]enkephalin has been synthesised as a potentially selective substrate for enkephalin dipeptidyl carboxypeptidase (enkephalinase) activity in brain. Incubations in the presence of homogenates and particulate fractions from rodent and human brain result in the formation of [3H]Tyr-D-Ala-Gly, which can be conveniently isolated by polystyrene bead column chromatography. The enzyme activity responsible for the hydrolysis of the Gly3-Phe4 amide bond of this substrate displays close resemblance to that hydrolysing the natural enkephalins at the same level. In addition, enkephalinase activity characterised in postmortem human brain is closely similar to that in rodent brain, with regard to optimal pH and apparent affinities of various substrates and inhibitors, including the potent compound thiorphan. Enkephalinase activity is distributed in a highly heterogeneous fashion among regions of human brain, the highest levels being found in globus pallidus and pars reticulata of the substantia nigra. This distribution is poorly correlated with that of opiate receptor binding sites but displays some resemblance to that of reported Met5-enkephalin levels.
化合物[3H]酪氨酰1，D-丙氨酰2，亮氨酰-OH5]脑啡肽已被合成，作为一种潜在的选择性底物，用于检测脑中脑啡肽二肽基羧肽酶（脑啡肽酶）的活性。在存在来自啮齿动物和人类大脑的匀浆和微粒体部分的情况下进行孵育，会形成[3H]酪氨酰-D-丙氨酰-甘氨酸，可通过聚苯乙烯珠柱色谱法方便地分离出来。负责水解该底物甘氨酰3-苯丙氨酰4酰胺键的酶活性与在相同水平水解天然脑啡肽的酶活性极为相似。此外，就最佳pH值以及各种底物和抑制剂（包括强效化合物硫醇苯丙氨酸）的表观亲和力而言，在死后人类大脑中表征的脑啡肽酶活性与啮齿动物大脑中的活性非常相似。脑啡肽酶活性在人类大脑区域中以高度异质的方式分布，在苍白球和黑质网状部中水平最高。这种分布与阿片受体结合位点的分布相关性较差，但与报道的甲硫氨酰5-脑啡肽水平的分布有一些相似之处。
