Weinberger S B, Martinez J L
Department of Psychology, University of California, Berkeley.
J Pharmacol Exp Ther. 1988 Oct;247(1):129-35.
Based on differences in total metabolite accumulation in the presence or absence of selective peptidase inhibitors, rat plasma is found to have its own unique pattern of enkephalin hydrolysis. Approximately 85-90% of the hydrolysis of [leu]enkephalin is attributed to the combined action of aminopeptidase M and angiotensin converting enzyme, whereas "enkephalinase" and aminopeptidase MII activity against [leu]enkephalin are not detectable. Similarly, 80-90% of the hydrolysis of D-ala2-[L-leu] enkephalin (DALLE) is due to the combined action of aminopeptidase M and angiotensin converting enzyme, whereas aminopeptidase MII and enkephalinase activity against this substrate also could not be detected. This is in contrast to the high susceptibility to hydrolysis by enkephalinase, and the low susceptibility to aminopeptidase activity, for DALLE in brain tissue. Among other alternatives, it is suggested that enkephalin hydrolysis in plasma may appear to be unique because of differences in enzyme conformation and/or the availability of a substance(s) that competes with, or alters the binding of, [leu] enkephalin, DALLE or the inhibitors to the enzymes.
基于在存在或不存在选择性肽酶抑制剂的情况下总代谢物积累的差异，发现大鼠血浆具有其自身独特的脑啡肽水解模式。[亮氨酸]脑啡肽约85 - 90%的水解归因于氨肽酶M和血管紧张素转换酶的联合作用，而未检测到针对[亮氨酸]脑啡肽的“脑啡肽酶”和氨肽酶MII活性。同样，D - 丙氨酸2 - [L - 亮氨酸]脑啡肽（DALLE）约80 - 90%的水解是由于氨肽酶M和血管紧张素转换酶的联合作用，而针对该底物的氨肽酶MII和脑啡肽酶活性也未检测到。这与脑组织中DALLE对脑啡肽酶水解的高敏感性和对氨肽酶活性的低敏感性形成对比。在其他可能性中，有人提出血浆中脑啡肽水解可能因其酶构象的差异和/或与[亮氨酸]脑啡肽、DALLE或抑制剂竞争或改变其与酶结合的一种或多种物质的可用性而显得独特。
