Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.15.1 (ACE)
 18,300 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Fractions highly enriched in plasma membrane, endoplasmic reticulum or brush border were prepared from homogenized rat kidney cortex. Kallikrein was concentrated in the plasma-membrane fraction, but not in the brush border of the proximal tubules. Kininase II or angiotensin I-converting enzyme was localized in the brush-border membrane. It is suggested that kallikrein in the urine may originate from the plasma membrane of the distal tubules and the conversion of angiotensin I and the inactivation of bradykinin may occur on the lumen membrane of the proximal tubular cells.
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PMID:Isolation of membrane-bound renal kallikrein and kininase. 17 90

Cortex of rat kidney was homogenized and fractions enriched in plasma membrane, endoplasmic reticulum or brush border were prepared by several techniques of differential centrifugation. The identity and homogeneity of the membrane fragments were investigated by assaying marker enzymes and by transmission and scanning electron microscopy. Kallikrein was present in both plasma-membrane- and endoplasmic-reticulum-enriched fractions isolated by two fractionation procedures. Kallikrein was highly concentrated in a plasma-membrane fraction but was absent from the brush-border membrane of proximal tubular cells. Cells of transplanted renal tumours of the rat, originating from the proximal tubule, had no kallikrein activity. Kininase activity, angiotensin I-converting enzyme (kininase II) and angiotensinase were found in a plasma-membrane-enriched fraction and especially in the fraction containing isolated brush border. It is suggested that after renal kallikrein is synthesized on endoplasmic reticulum, it is subsequently reoriented to a surface membrane for activation and release. Renal kallikrein may enter the tubular filtrate distal to the proximal tubules. The brush-border membrane of proximal tubule is the major site of inactivation of kinins and angiotensin II..
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PMID:Isolation of membrane-bound renal enzymes that metabolize kinins and angiotensins. 18 28

1. Fractions highly enriched in plasma membrane, endoplasmic reticulum or brush border were prepared from rat kidney cortex. Kallikrein was concentrated in the plasma membrane fraction, but not in the brush border fraction. Angiotensin I-converting enzyme (kininase II) and angiotensinase were localized in the brush border membrane. 2. It is suggested that kallikrein in the urine may originate from plasma membrane distal to the brush border of proximal tubules and the conversion of angiotensin I and the inactivation of bradykinin and angiotensin II may occur on the lumen membrane of the proximal tubular cells.
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PMID:Isolation of renal membranes that contain kallikrein, angiotensin I-converting enzyme (kininase II) and angiotensinase in the rat. 19 12

Iloprost (ZK 36 374), a stable analog of carbaprostacyclin, was infused for 72 h to nine patients with advanced obliterative arterial disease. Iloprost caused a marked vasodilation and a compensatory increase in cardiac output. The glomerular filtration rate increased by 45% and tubular reabsorption of sodium and water were reduced by 80% and 107%, respectively. The urine excretion rate increased by 122%. Tubular handling of potassium and calcium were not influenced by iloprost but magnesium reabsorption was stimulated. The renin-angiotensin system was not activated while serum angiotensin converting enzyme activity was decreased. Kallikrein excretion in urine was increased 4.4-fold but plasma kininogen, a substrate for kallikrein in producing vasoactive kinins, was unaffected by the drug. Plasma levels of 6-keto-PGF1 alpha and TxB2 were decreased and their excretion in urine increased. Plasma catecholamines were not changed by iloprost. Several of the changes persisted for at least the first postinfusion day. The results indicate that iloprost increases urine excretion rate by increasing glomerular blood flow and by inhibiting sodium and water reabsorptions. The kinin-forming system, but not the renin-angiotensin system or plasma catecholamines, may be activated. The decrease in plasma level of prostanoids can be, at least partly, due to their increased excretions in urine.
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PMID:Effects of a prostacyclin analog iloprost on kidney function, renin-angiotensin and kallikrein-kinin systems, prostanoids and catecholamines in man. 241 61

To clarify the relationship between kallikrein-kinin and renin-angiotensin systems, glandular kallikrein, renin and angiotensin converting enzyme in the submandibular gland, the kidney and plasma were investigated in streptozotocin diabetic and spontaneously hypertensive rats. Kallikrein content in the submandibular gland, the kidney and plasma of diabetic rats was found to be decreased compared with nondiabetic controls. Renin activity in diabetic rats was also reduced in the submandibular gland, but the activity showed no significant changes in the kidney and plasma. The activity of angiotensin converting enzyme (ACE) in plasma significantly increased in diabetic rats. On the other hand, kallikrein content in hypertensive rats was depressed in the kidney, while the content was unchanged in the submandibular gland and plasma. Renin activity in hypertensive rats was found to be higher than that of normotensive rats in the submandibular gland, but the activity showed no remarkable changes in the kidney and plasma. ACE activity in plasma markedly decreased in hypertensive rats in contrast to diabetic rats. In hypertensive-diabetic rats, changes in the levels of these enzymes in tested materials were similar to those of diabetic rats. From these results it is reasonable to assume that (1) reduced kallikrein generation and elevated ACE activity may induce impaired kinin formation and contribute to the development of diabetes mellitus apart from the presence of hypertension and (2) low kallikrein content in the kidney could cause hypertension.
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PMID:Glandular kallikrein, renin and angiotensin converting enzyme of diabetic and hypertensive rats. 255 14

The intrarenal kallikrein-kinin system was studied during the acute phase of renovascular hypertension induced by renal artery constriction and during teprotide inhibition of kininase II in the dog. Kallikrein-like activity measured by both kininogenase and esterolytic assays, was increased during renal artery constriction (p less than 0.5) and (p less than 0.01). The administration of teprotide resulted in a further increase of renal cortical kallikrein-like activity and inhibited kininase II activity (p less than 0.01). Following the inhibition of kininase II, the plasma concentration of kininogen was also significantly decreased (p less than 0.01). These results suggest that kininase II inhibition may increase levels of intrarenal and plasma kinins and that decreased degradation of kinin peptides may contribute significantly to the acute hypertensive effect of teprotide.
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PMID:Intrarenal kallikrein-kinin activity in acute renovascular hypertension in dogs. 285 35

A zinc dependent serratial 56K protease caused enhancement of vascular permeability followed by edema formation when injected into the guinea pig peripheral cornea, the subconjunctival space, or the skin. Because this enhancement was not affected by antihistamine, involvement of the kinin-generating system in this permeability enhancement was investigated. The 56K protease induced permeability much greater extent than that by bradykinin on weight basis, and more so on molar basis. The phenomenon was inhibited by soybean trypsin inhibitor, a well known inhibitor of plasma kallikrein, and also by corn trypsin inhibitor, which is the best inhibitor of the activated Hageman factor. In vitro experiments using numbers of synthetic peptide substrates, the 56K protease exhibited a similar substrate specificity to that of plasma kallikrein. Kallikrein is a known endogenous activator of Hageman factor. The enhancement by 56K protease was greatly augmented by inhibition of kininase II with Glu-Trp-Arg-Pro-Gln-Ile-Pro-Pro-OH (SQ 20,881), suggesting generation of bradykinin. Thus, these results indicate that the enhancement of vascular permeability induced by the 56K protease is caused by an activation of Hageman factor by 56K protease followed by subsequent activation of cascade amplification, and resulted in kinin generation in vivo.
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PMID:Enhancement of vascular permeability upon serratial infection: activation of Hageman factor--kallikrein--kinin cascade. 288 Apr 83

The possible roles of vasodilatory prostanoids and the kallikrein-kinin system in the antihypertensive action of the angiotensin-converting enzyme (kininase II) inhibitor captopril were examined in spontaneously hypertensive rats. Captopril (20, 50 or 100 mg/kg daily orally) reduced blood pressure markedly and dose-dependently. It also increased water consumption and urine excretion, measured on the 5th day of treatment. The 24-hr urinary excretion of PGE2 was not changed, whereas that of PGF2 alpha and TxB2 tended to be enhanced. A clear increase, significant with all doses of captopril, occurred in the urinary excretion of 6-keto-PGF1 alpha. Kallikrein excretion in urine was suppressed by the two larger doses of captopril. The markedly augmented urinary excretion of 6-keto-PGF1 alpha, the stable metabolite of vasodilatory prostacyclin (PGI2), suggests that increased prostacyclin production may participate in the antihypertensive mechanism of captopril. Vasodilatory kinins can also contribute, since the captopril-induced decrease in kallikrein may reflect accumulation of kinins due to their reduced metabolism.
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PMID:Effects of captopril on the urinary excretion of prostanoids and kallikrein in spontaneously hypertensive rats. 354 94

Responses of smooth muscle to kallikreins (EC 3.4.21.8) are generally considered to result from kinin formation. This premise was reexamined with the isolated rat uterus. Rat urinary kallikrein or bradykinin produced dose-dependent contractions of rat uterus but kallikrein was 5-fold more potent than bradykinin. Kallikrein caused an immediate series of rhythmic contractions which could be increased gradually with subsequent addition of kininogen substrate. Kallikrein-induced contractions were unaffected by carboxypeptidase B or a bradykinin antiserum whereas bradykinin-induced contractions were attenuated or abolished. Other serine proteinases, including trypsin, either did not induce contraction in the absence of added kininogen or did so minimally. Although small amounts of kininogen-like substrate were found in uterine tissue, detectable kinin levels (greater than 4 pg) could not be found in bathing media during maximal kallikrein-induced contractions or after uterine tissue was incubated with high concentrations of the enzyme in the presence of SQ 20881, a kininase II inhibitor. The data suggest that uterine contraction produced by a homologous kallikrein does not involve kinin formation but results from an action of this serine proteinase upon other accessible systems coupled to the contractile response.
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PMID:Kallikrein-induced uterine contraction independent of kinin formation. 694 18

The endothelial cell should be regarded as a highly active metabolic and endocrine organ interacting with the blood streak and the interstitium. Kinins are vasodepressor hormones that may participate in local blood flow regulation as part of an autocrine-paracrine system. We have previously reported that tissue kallikrein, its mRNA and kininogen are present in vascular tissue. The present study was undertaken to examine the release of the components of this system from isolated perfused rat vessels. These vessels were perfused at 4 ml/min with physiological saline solution containing 3% Ficoll and 0.1% BSA. Kallikrein was released into the perfusate at a rate of 75 +/- 5 ng Bk/100 g bw/30 min (n = 10). Kininogen was released at a rate of 55 +/- 5 pg Bk/100 g bw/30 min. Pre-treatment with puromycin, a protein synthesis inhibitor, significantly reduces kallikrein and kininogen release. Vascular derived kinins were released at a constant rate of 38 +/- 6 pg Bk/100 g bw/30 min for at least 120 min. This basal kinin release was increased 3-fold when perfused with the angiotensin converting enzyme inhibitor ramiprilat (p < 0.05). When purified kininogen was added to the physiological saline solution, immunoreactive kinins in the perfusate increased from 42 +/- 7 to 3140 +/- 210 pg Bk/100 g bw/30 min (n = 6; p < 0.002). Increase in flow rate (from 2 ml/min up to 4 ml/min and 8 ml/min) causes a parallel increase in the release of kinins (from 32 +/- 4 up to 48 +/- 6 and 62 +/- 8 pg Bk/100 g bw/30 min, respectively; p < 0.01); the increase may be due to the effect of shear stress upon the endothelial cells. The present data confirm that vascular tissue synthesizes and releases continuously kallikrein, kininogen and kinins. Vascular kinins induce potent vasodilatation through the release of prostacyclin, nitric oxide and endothelium-derived hyperpolarization factor, and some of the converting enzyme inhibitors effect may be explained by potentiation of vascular-derived kinins.
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PMID:Release of endothelial-derived kallikrein, kininogen and kinins. 983 May 4


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