Marini M, Urbani A, Bongiorno L, Gilardi E, Roda L G
Dipartimento di Medicina Sperimentale, Universitá di Roma Tor Vergata, Italy.
Peptides. 1996;17(3):451-9. doi: 10.1016/0196-9781(95)02149-3.
Hydrolysis and inhibition of hydrolysis of leucine enkephalin in Oryctolagus plasma were studied by kinetics and chromatographic techniques. By data obtained, in this species, enkephalins are degraded by the same enzymes active in other mammals: aminopeptidases, dipeptidylaminopeptidases, and dipeptidylcarboxypeptidases. At variance with data obtained in other species, where enkephalins are hydrolyzed mostly by aminopeptidases, in Oryctolagus Leu-enkephalin hydrolysis is mainly due to dipeptidylcarboxypeptidases, whereas aminopeptidases contribution is the minimum of all three enzyme groups. Comparative analyses performed in the presence and in the absence of plasma inhibitors indicate that the ability of these substances to reduce substratum hydrolysis is very limited. On the contrary, the specific hydrolysis pattern evidenced appears to originate primarily from selective inhibition of the three groups of enzymes. Results obtained appear consistent with a role of plasma inhibitors in tuning hydrolysis to specific substrata, without appreciably modifying the amount of the substratum degraded.
采用动力学和色谱技术研究了亮氨酸脑啡肽在兔血浆中的水解及水解抑制情况。根据所获数据，在该物种中，脑啡肽由与其他哺乳动物中活性相同的酶降解：氨肽酶、二肽基氨肽酶和二肽基羧肽酶。与在其他物种中所获数据不同，在其他物种中脑啡肽主要由氨肽酶水解，而在兔中亮氨酸脑啡肽的水解主要归因于二肽基羧肽酶，而氨肽酶的作用在所有三类酶中最小。在有和没有血浆抑制剂存在的情况下进行的比较分析表明，这些物质降低底物水解的能力非常有限。相反，所证实的特定水解模式似乎主要源于对这三类酶的选择性抑制。所获结果似乎与血浆抑制剂在将水解调节至特定底物方面的作用一致，而不会明显改变降解底物的量。
