Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.24.11 (CD10)
 9,792 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Neutral endopeptidase (NEP) (enkephalinase, EC 3.4.24.11) and angiotensin converting enzyme (ACE) are two peptidases that can cleave the C-terminal dipeptide bradykinin(8-9) from bradykinin. To determine whether these peptidases play roles in modulating kinin-induced contractions in the airways, we studied the effects of captopril, an ACE inhibitor, and of leucine-thiorphan and phosphoramidon, two NEP inhibitors, on the contractile responses to bradykinin and lysyl-bradykinin in isolated segments of ferret trachea. Bradykinin and lysyl-bradykinin-induced contractions in a concentration-dependent fashion (P less than .001), with a threshold of 10(-7) M and 5 x 10(-7) M, respectively. In contrast, the bradykinin(8-9) and the N-terminal heptapeptide bradykinin(1-7), the major fragments of hydrolysis of bradykinin by NEP and ACE, had a very weak or no effect on tracheal contraction in concentrations as great as 10(-5) M. Captopril, leucine-thiorphan and phosphoramidon (each inhibitor at 10(-5) M, 15 min) shifted the concentration-response curves to lower concentrations by approximately 1 to 1.5 log U (P less than .05). Both NEP inhibitors and the ACE inhibitor potentiated the response to bradykinin in a concentration-dependent fashion (P = .0001), and the combination of phosphoramidon and captopril resulted in an additive potentiation of bradykinin-induced contraction (P less than .02). [D-Pro2-D-Trp7,9]-substance P, a substance P antagonist, did not modify the potentiation of bradykinin-induced contraction by NEP inhibitors.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Neutral endopeptidase and angiotensin converting enzyme inhibitors potentiate kinin-induced contraction of ferret trachea. 327 79

A multicatalytic endopeptidase (ME) with three distinct activities, chymotrypsin-like, cucumisin-like, and trypsin-like, occurred in all rat tissues examined with highest activities in kidney, testes, liver, and spleen; they were assayed with benzyloxycarbonyl-Gly-Gly-Leu-p-nitroanilide (Z-Gly-Gly-Leu-pNA), benzyloxycarbonyl-Leu-Leu-Glu-2-naphthylamide (Z-Leu-Leu-Glu-2NA), and benzyloxycarbonyl-Gly-Gly-Arg-2-naphthylamide (Z-Gly-Gly-Arg-2NA), respectively. All three activities were recovered from a single protein band on a polyacrylamide gel after electrophoresis of purified human kidney ME. The native enzyme had a Mr of 650,000, and it consisted of about 5,135 amino acid residues. After denaturation and electrophoresis on sodium dodecyl sulfate (SDS)-polyacrylamide gels kidney ME dissociated into several low Mr components ranging from 23,000 to 33,000. Kidney ME had a pH optimum of 7.6-8.1 with Z-Gly-Gly-Leu-pNA, 7.3 with Z-Leu-Leu-Glu-2NA, and 9.8 with Z-Gly-Gly-Arg-2NA. SDS enhanced chymotrypsin- and cucumisin-like activities by two to three times whereas trypsin-like activity was not enhanced. The specificity constant (kappa cat/Km) of human kidney ME for Z-Gly-Gly-Leu-pNA was 6.7 X 10(3) M-1 S-1; Z-Gly-Gly-Leu-2NA was not hydrolyzed. The specificity constant for Z-Leu-Leu-Glu-2NA was similar to, and for Z-Gly-Gly-Arg-2NA was one half of that for Z-Gly-Gly-Leu-pNA. ME cleaves only the Phe5-Ser6 bond of bradykinin (BK); however, all three ME activities were inhibited by BK. Strong inhibition of ME by albumin suggests that ME is involved in cleavage of larger polypeptides. Antipain and leupeptin almost completely inactivated the trypsin-like activity whereas they had no significant effect on the other two activities. ME is not a metal-loenzyme nor is the serine residue essential for its activities; however, thiol groups are involved. Na+ and K+ inhibited all ME activities. Trypsin-like activity was more sensitive to divalent cations than the other two.
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PMID:A multicatalytic high-molecular-weight neutral endopeptidase from human kidney. 331 Sep 3

Previous attempts to liberate T kinin from T kininogen [Moreau et al. (1986) Eur. J. Biochem. 159, 341-346; Gutman et al. (1988) Eur. J. Biochem. 171, 577-582] have shown that complete fragmentation of the precursor molecule into inhibitory peptides was achieved before any vasoactive peptide was released, suggesting a possible physiological significance for this phenomenon. In this study, cysteine-proteinase-inhibiting properties of rat T kininogen and of its proteolytic fragments issuing from trypsin and submaxillary gland endopeptidase k hydrolysis, have been investigated using rat lysosomal cathepsins B, H and L, papain and bovine calpains I and II. All three lysosomal cathepsins were inhibited by T kininogen but tighter interactions were observed with cathepsin L and papain. Though higher Ki values were obtained for cathepsins B and H, rate constants for association were found to have high and almost similar values (in the 10(6) M-1 s-1 range) whatever the enzyme used. Proteolytic fragments also inhibited cathepsin L and papain very strongly and even better than the entire molecule for some of them, but no significant inhibition of cathepsins B and H was observed. Bovine calpains were not inhibited by T kininogen nor by its proteolytic fragments. From the results of this kinetic analysis, which indicates that both the association and the dissociation of lysosomal cysteine proteinases with T kininogen may occur rapidly, an hypothesis has been put forward on the possible in vivo functioning of T kininogen as a proteinase inhibitor.
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PMID:Cysteine-proteinase-inhibiting function of T kininogen and of its proteolytic fragments. 335 89

Bradykinin-hydrolyzing enzyme was purified 200-fold from a soluble fraction of cornified cells from 2-day-old rat epidermis. The enzyme has an Mr of 80,000 as identified by SDS polyacrylamide gel electrophoresis and HPLC gel filtration. The isoelectric point of the enzyme is 5.05. The enzyme hydrolyzed Phe5-Ser6 of bradykinin and seven bradykinin-related peptides, and Tyr5-Ser6 of Tyr5-bradykinin. Production of bradykinin fragments, Arg-Pro-Pro-Gly-Phe and Ser-Pro-Phe-Arg, proceeded in a stoichiometric fashion. Km and Vmax values for bradykinin were 33 microM and 22.2 mumol/min per mg, respectively. The enzyme did not hydrolyze azocasein, denatured hemoglobin or synthetic substrates for other epidermal proteinases. The enzyme activity was enhanced by reducing agents and inhibited by sulfhydryl-blocking agents and divalent cations. Diisopropyl fluorophosphate and phenylmethylsulfonyl fluoride had no effects. The enzyme has a pH optimum of 7.0-7.5 and is stable at 4 degrees C for 1 month, but loses activity completely at 60 degrees C for 10 min. The epidermal endopeptidase differs in several properties from endooligopeptidase A purified from brain which hydrolyzes Phe5-Ser6 of bradykinin.
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PMID:Purification and characterization of bradykinin-hydrolyzing enzyme from 2-day-old rat epidermis. 336 52

Although kinins have been reported to affect cerebral vascular tone and permeability, their actions are not potentiated by angiotensin converting enzyme inhibitors. To investigate cerebral vascular kinin metabolism, porcine cerebral microvessels were isolated by differential sieving and centrifugation and characterized by microscopic examination and marker enzyme enrichment. Purified microvessels contained a membrane-bound carboxypeptidase which hydrolyzed the C-terminal Phe-Arg bond of both kallidin and bradykinin. Hydrolysis was optimal at pH 7.0, was activated more than 300% by 0.1 mM CoCl2, and was inhibited by o-phenanthroline and the carboxypeptidase N (EC 3.4.17.3) inhibitor DL-2-mercaptomethyl-3-guanidino-ethylthiopropanoic acid (MERGETPA) (IC50 = 2 microM). Conversely, inhibitors of angiotensin I converting enzyme (captopril), neutral endopeptidase (phosphoramidon), post proline cleaving enzyme (Z-Pro-prolinal), dipeptidyl(amino)peptidase IV (diprotin A) and amino-peptidase M (amastatin) had no effect. When the rates of C-terminal hydrolysis of kallidin by detergent-solubilized cerebral microvasculature were determined over a range of substrate concentrations (16.6 to 250 microM), the Km and Vmax values obtained were 26.0 +/- 3.0 microM and 14.7 +/- 1.3 nmol/min/ml (N = 4) respectively. These data suggest that a cerebral microvascular carboxypeptidase may play a role in vivo in modulating the effects of kinins on cerebral blood flow and permeability and in preventing circulating kinins from crossing the blood-brain barrier.
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PMID:Kallidin and bradykinin metabolism by isolated cerebral microvessels. 339 72

Post-proline cleaving enzyme (PPCE; EC 3.4.21.26) is a proline specific endopeptidase capable of hydrolyzing biologically active peptides. The present studies examined the hydrolysis of kinin- and angiotensin-related peptides by cytosolic PPCE purified from porcine kidney. PPCE hydrolysis of the synthetic substrate Z-Gly-Pro-MCA (30.7 +/- 0.3 mumol . min-1 . mg-1) was competitively inhibited by saralasin, bradykinin, des(Arg9)bradykinin, [Leu8], des(Arg9)bradykinin and angiotensin II (IC50 = 0.5 to 7.0 microM). Qualitative TLC studies demonstrated that each peptide was degraded by hydrolysis on the carboxyl side of proline residues (positions 7 or 8). Quantitative HPLC studies established that peptide degradation was optimal at pH 8.2 to 8.7 and was inhibited by the specific PPCE inhibitor Z-Pro-prolinal (IC50 = 0.8 +/- 0.1 nM). Conversely, degradation was unaffected by inhibitors of aminopeptidases (amastatin), neutral endopeptidase (phosphoramidon), carboxypeptidase N (MERGETPA) or angiotensin I converting enzyme (captopril). Apparent Km values, obtained from Lineweaver-Burk analysis, were comparable for all kinin and angiotensin peptides (Km = 5.5 to 12.8 microM), whereas Vmax values ranged from 1.7 mumol . min-1 . mg-1 for angiotensin II to 0.44 mumol . min-1 . mg-1 for saralasin. These data are consistent with a role for PPCE in the degradation of kinins and angiotensin in vivo.
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PMID:Kinin and angiotensin metabolism by purified renal post-proline cleaving enzyme. 347 49

In order to identify which peptidases are involved in the catabolism of neurotensin in the CNS, [3H-Tyr3,11]-neurotensin was superfused over rat hypothalamic slices in the presence and absence of peptidase inhibitors. The degree of degradation of the peptide was determined by reverse phase HPLC separation of 3H-labelled neurotensin from 3H-labelled products. Very little degrading activity was released from the slice into the medium during the superfusion. In the absence of inhibitors, 20 to 50% of 3H-neurotensin was degraded giving mainly 3H-Tyr along with other unidentified 3H-labelled products. Inhibitors of endopeptidase 24.11 (phosphoramidon) and proline endopeptidase (antibody) had no effect on the degradation. Captopril, an inhibitor of angiotensin converting enzyme, had a small inhibitory effect. In contrast, dynorphin(1-13), an inhibitor of a soluble, thiol dependent metallopeptidase which hydrolyses neurotensin at Arg8-Arg9, gave greater than 80% inhibition of 3H-neurotensin degradation in the slice preparation. 1,10-Phenanthroline, an inhibitor of metallopeptidases, was also an effective inhibitor. The dynorphin sequence responsible for the inhibition contains the Arg6-Arg7 bond. Other peptides (bradykinin and angiotensin) which are substrates of the soluble metallopeptidase also inhibited neurotensin breakdown by the slice. This evidence suggests that this thiol dependent metalloendopeptidase is the major neurotensin catabolizing enzyme in hypothalamic slices.
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PMID:Peptidases involved in the catabolism of neurotensin: inhibitor studies using superfused rat hypothalamic slices. 352 99

A high-Mr neutral endopeptidase-24.5 (NE) that cleaved bradykinin at the Phe5-Ser6 bond was purified to apparent homogeneity from human lung by (NH4)2SO4 fractionation, ion-exchange chromatography and gel filtration. The final enzyme preparation produced a single enzymically active protein band after electrophoresis on a 5% polyacrylamide gel. Human lung NE had an Mr of 650,000 under non-denaturing conditions, but after denaturation and electrophoresis on an SDS/polyacrylamide gel NE dissociated into several lower-Mr components (Mr 21,000-32,000) and into two minor components (Mr approx. 66,000). The enzyme activity was routinely assayed with the artificial substrate Z-Gly-Gly-Leu-Nan (where Z- and -Nan represent benzyloxycarbonyl- and p-nitroanilide respectively). NE activity was enhanced slightly by reducing agents, greatly diminished by thiol-group inhibitors and unchanged by serine-proteinase inhibitors. Human lung NE was inhibited by the univalent cations Na+ and K+. No metal ions were essential for activity, but the heavy-metal ions Cu2+, Hg2+ and Zn2+ were potent inhibitors. With the substrate Z-Gly-Gly-Leu-Nan a broad pH optimum from pH 7.0 to pH 7.6 was observed, and a Michaelis constant value of 1.0 mM was obtained. When Z-Gly-Gly-Leu-Nap (where -Nap represents 2-naphthylamide) was substituted for the above substrate, no NE-catalysed hydrolysis occurred, but Z-Leu-Leu-Glu-Nap was readily hydrolysed by NE. In addition, NE hydrolysed Z-Gly-Gly-Arg-Nap rapidly, but at pH 9.8 rather than in the neutral range. Although human lung NE was stimulated by SDS, the extent of stimulation was not appreciable as compared with the extent of SDS stimulation of NE from other sources.
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PMID:A high-molecular-mass neutral endopeptidase-24.5 from human lung. 355 24

This paper sets out to review some recent work on the role of endopeptidase-24.11. In renal brush borders, this enzyme is usually the only endopeptidase present among a host of exopeptidases, yet it appears to be the rate limiting step in the hydrolysis of a number of peptides, including bradykinin and the angiotensins. Endopeptidase-24.11 is widely, but not ubiquitously distributed--present not only in renal and intestinal brush borders, but also in lymph nodes, glandular tissues and the nervous system. All the last groups are rich in neuropeptides. The endopeptidase exhibits high specificity constants for a number of these potential substrates, including tachykinins, enkephalins and bradykinin. In the brain, immunocytochemical studies have shown colocalization of the enzyme and substance P. Thus, endopeptidase-24.11 has the appropriate topology, specificity, kinetic properties and localization to play a role in the metabolism of regulatory peptides.
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PMID:Regulatory peptide metabolism at cell surfaces: the key role of endopeptidase-24.11. 355 72

Largomycin, an antibiotic and antitumor protein, purified from the culture broth of Streptomyces pluricolorescens, displayed specific proteolytic activity. Pure largomycin did not degrade a number of substrates commonly used for detection of aminopeptidase, endopeptidase and carboxypeptidase activity. Pure largomycin degraded angiotensin II, bradykinin, a few dipeptides and a number of proteins of KB cell plasma membranes. The biological activity and the proteolytic activity of largomycin showed similar temperature-dependent patterns, suggesting that one protein is responsible for both activities. The apoprotein of largomycin, which did not show antibiotic activity, contained the proteolytic activity.
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PMID:Proteolytic activity of largomycin. 389 21


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