纯化的兔肺血管紧张素转换酶对P物质的羧基末端三肽基水解作用以及卡托普利和MK - 422对P物质体内活性的增强作用。
Carboxyl-terminal tripeptidyl hydrolysis of substance P by purified rabbit lung angiotensin-converting enzyme and the potentiation of substance P activity in vivo by captopril and MK-422.
作者信息
Cascieri M A, Bull H G, Mumford R A, Patchett A A, Thornberry N A, Liang T
出版信息
Mol Pharmacol. 1984 Mar;25(2):287-93.
The hydrolysis of substance P is catalyzed by purified rabbit lung angiotensin-converting enzyme (peptidyldipeptide hydrolase, EC 3.4.15.1). The kcat/Km for the reaction at 37 degrees is 3.3 +/- 0.3 X 10(3) M-1 sec-1, which is 60 times less than that which has been reported for the hydrolysis of angiotensin I. The initial site of hydrolysis is the antipenultimate peptide bond, which generates the tripeptide amide (Gly-Leu-Met-NH2). This hydrolysis is inhibited by the angiotensin-converting enzyme inhibitors captopril, MK-422, and EDTA, and is dependent on the concentration of chloride ion. Both captopril and MK-422 potentiate the substance P-induced stimulation of salivation in rats. Thus, angiotensin-converting enzyme may be one of the enzymes that degrade substance P in vivo.
P物质的水解由纯化的兔肺血管紧张素转换酶（肽基二肽水解酶，EC 3.4.15.1）催化。37℃时该反应的kcat/Km为3.3±0.3×10³M⁻¹s⁻¹，这比报道的血管紧张素I水解的kcat/Km小60倍。水解的起始位点是倒数第二个肽键，生成三肽酰胺（甘氨酸-亮氨酸-甲硫氨酸-NH₂）。这种水解受到血管紧张素转换酶抑制剂卡托普利、MK-422和EDTA的抑制，并且依赖于氯离子浓度。卡托普利和MK-422均增强P物质诱导的大鼠唾液分泌。因此，血管紧张素转换酶可能是体内降解P物质的酶之一。
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