Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.5.1.4 (deaminase)
5,113 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Using a direct radioimmunoassay and a kininogenase assay, we determined that 68% of rat urinary kallikrein was enzymatically active while 32% was in an inactive form which was activated by trypsin. Inorganic cations, at concentrations found in rat urine, were inhibitory in an amidase assay but appeared to potentiate kininogenase activity of pure rat urinary kallikrein. In random urines, kinin concentration was 4.2 +/- 0.7 ng/ml. Trypsinization of the urines generated 52.9 +/- 25.8 ng kinin/ml, indicating that kininogen was present. The rate of kinin formation in vivo may depend on the availability of kininogen and the concentration of inorganic cations in urine, as well as on other well-recognized factors, such as the kallikrein activity of the urine.
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PMID:Components of the kallikrein-kinin system in rat urine. 656 18

We studied the effect of ions on the ability of purified human urinary kallikrein to cleave its natural substrate (kininogen) as well as two synthetic substrates, tosylarginine [3H]methyl ester and Pro-Phe-Arg-[3H]benzylamide. The kininogenase activity of kallikrein is markedly dependent upon the concentration of cations in vitro. Kininogenase activity is very low when measured in a low electrolyte buffer. The addition of cations to the reaction mixture increases activity by up to 27-fold. Maximum activity is achieved with 100 mM sodium, 100 mM potassium, or 20 mM magnesium. The activity is stable at higher concentrations of cation. Renal kallikrein is believed to act within distal tubular fluid in vivo. The concentration of cations in this fluid varies widely in response to alterations in salt and water metabolism. Thus, the relationship of kininogenase activity to the concentration of cations demonstrated in vitro may be relevant to the activity of kallikrein at its presumed site of action in the kidney. In separate experiments, we evaluated the effect of ions on the amidase and esterase activities of kallikrein which are the basis of several assays in routine use for physiological studies. In contrast to their stimulatory effect on kininogenase activity, cations inhibit amidase and to a lesser extent esterase activity. Additional studies indicate that urinary cations probably account entirely for the well known ability of normal urine to inhibit the amidase and esterase activities of kallikrein.
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PMID:The effect of cations on the activity of human urinary kallikrein. 692 Dec 2

Factor XI (FXI) deficiency is associated with an abnormal bleeding state. The extent of bleeding does not correlate well with the plasma concentration of FXI, and it has been suggested that also unknown factors interfere with the bleeding tendency. In a recent paper (Thromb. Res. 74, 477-485, 1994) we found that FXIa activated in human plasma was present in association with part of factor XIIa (FXIIa) and part of kallikrein, influencing their functional activities. Should the activity level of FXIa also be altered by the other contact factors this might provide one approach to the problem of the failure of assays of FXIa to correlate with bleeding tendency. In the present study we have developed an assay procedure for FXIa based on its amidolytic (S-2366) activity, and allowing at the same time a quantification of the amount of FXIa associated to kallikrein. The total amidase activity obtained was separated into two main fractions by use of soybean trypsin inhibitor (STI), corn inhibitor (CI) and lima bean trypsin inhibitor (LTI). One fraction contained free FXIa which could be specifically blocked by LTI. An inhibitor resistant fraction was found to contain FXIa inactive in association with kallikrein. The content of FXIa could be assessed in experiments with mixtures of normal plasma and plasma deficient in prekallikrein, and was taken into account in the calculations. This fraction increased during storage of plasma at -70 degrees C. To obtain stable and comparable assay conditions the method was based on plasma stored for at least four weeks. The specificity of the method was verified by parallel radial immunodiffusion tests. The results imply that the activity level of FXIa is dependent on kallikrein present. If the experimental results has relevance to the situation under physiological conditions, they indicate one possible cause of the failure of assays of FXI to correlate with bleeding tendency.
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PMID:Amidolytic assay of factor XI in human plasma--significance of kallikrein for the activity measured. 763 4

The kallikrein-like serine proteinase nerve growth factor gamma (NGF-gamma) reacted with the plasma proteinase inhibitor human alpha 2-macroglobulin (h alpha 2M). The h alpha 2M subunits were cleaved, the electrophoretic mobility of h alpha 2M in nondenaturing polyacrylamide gels was increased, and the intrinsic fluorescence of h alpha 2M was increased with a slight blue-shift. These changes are well-characterized components of the alpha 2M/proteinase reaction mechanism. In N alpha-benzoyl-DL-arginine p-nitroanilide (BAPNA) hydrolysis experiments, the catalytic efficiency (kcat/KM) of the h alpha 2M-NGF-gamma complex was decreased by 98.5% compared with free NGF-gamma. This decrease is unique since other alpha 2M-proteinase complexes retain significant amidase activity. For comparison, we determined that the catalytic efficiency of alpha 2M-trypsin is decreased by 58% compared with free trypsin under equivalent conditions. The rate of NGF-gamma inhibition by h alpha 2M was (1.0 +/- 0.1) x 10(4) M-1 s-1 as determined by BAPNA hydrolysis. A similar value was determined by monitoring the change in intrinsic fluorescence. NGF-gamma, which was bound within the intact 7S NGF complex, also reacted with h alpha 2M, albeit at a very slow rate. This reaction may have depended exclusively on slow reversible dissociation of NGF-gamma from the 7S complex. NGF-gamma was rapidly inhibited by murine alpha 2M (m alpha 2M).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Reaction of nerve growth factor gamma and 7S nerve growth factor complex with human and murine alpha 2-macroglobulin. 767 24

The fibrinolytic system was studied in normal human plasma containing increasing concentrations of acetone up to 23.4 mmol l-1. Fibrinolytic activity measured as euglobulin clot lysis time [ECLT] and amidase activities toward chromogenic peptide substrates H-D-Valyl-L-Leucyl-L-Lysine-p-nitroanilide 2 HCl [S-2251], designed for plasmin determination, H-D-Valyl-L-Phenylalanyl-L-Lysine-p-nitroanilide 2 HCl [S-2390], designed for the determination of t-PA in plasma via plasminogen activation and H-D-Prolyl-L-Phenyl-Alanyl-L-Arginine-p-nitro-anilide 2 HCl [S-2302], designed for the determination of kallikrein and activated Hageman factor, increased when 15.7 mmol l-1 concentration of acetone was reached. A parallel increase of esterolytic [substrate: naphthol-AS-acetate] activity was observed in euglobulin fractions. Crossed immunoelectrophoresis [CIE] revealed changes in fibrinogen profiles of plasma enriched with acetone as compared to native plasma. These findings suggest that acetone present in plasma in concentrations comparable to those found in some pathological states might activate fibrinolytic system.
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PMID:Enhancement of fibrinolytic activity of human plasma in the presence of acetone. 799 40

We studied some of the components of the kininogen-kallikrein-kinin system, simultaneously, in plasma and synovial effusions of patients with inflammatory articular diseases. Plasma and tissue kallikrein like activity and kininogen levels were evaluated. Active plasma and tissue kallikreins in plasma and synovial fluid were detected by their amidase activity upon specific chromogenic substrates. Kininogen levels were determined by a bioassay. Both specific amidase activity of plasma and tissue kallikreins were augmented in synovial effusions in relation to their own plasma activity. Kininogen levels in synovial fluid tended to be diminished in relation to plasma, however statistical significance was not reached. The consumption of kininogen is probably related to kinin production. This finding together with increased activities of plasma and tissue kallikreins reinforce the involvement of kinins in pathogenesis of inflammatory articular diseases.
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PMID:Augmented plasma and tissue kallikrein like activity in synovial fluid of patients with inflammatory articular diseases. 874 Oct 10

The aim of the present study was to purify and identify a plasma protein fraction (PreR-Co) involved in renal prorenin activation and to explore its capacity to process plasma prorenin. PreR-Co was obtained from plasma as a single electrophoretic band by (NH(4))(2)SO(4) precipitation, Sephacryl S-200 HR gel filtration, anti-rat albumin immunoaffinity, and ion-exchange chromatography. The amidase, esterase, and kallikrein activities of PreR-Co were studied, as was its N-terminal amino acid sequence. Rat kidney extract or plasma (normal or previously treated with acid to pH 2.8) were incubated with PreR-Co for 15 minutes at 37 degrees C. Renin concentration was measured by incubation with homologous angiotensinogen. The same protocol was repeated with samples activated by trypsin. The N-terminal amino acid sequence was IIGGSMDAKGSFP, which had a homology of 90% with the beta-chain of haptoglobin, 69% with serine-proteases, and 65% with kallikreins. The renin concentration in rat kidney extract was 34+/-4 ng of angiotensin I (Ang I). mg of tissue(-1). h(-1). After PreR-Co or trypsin treatments, renin concentrations were 211+/-7 and 110+/-11 ng of Ang I. mg of tissue(-1). h(-1), respectively. The plasma renin concentration in normal plasma was 67.6+/-13.3 ng of Ang I. mL(-1). h(-1), and no significant difference was observed after PreR-Co treatment. However, a significant increase (202.8+/-7.8 ng of Ang I. mL(-1). h(-1); P<0.01) was found after trypsin treatment. The isolated PreR-Co acts on renal prorenin but not on plasma prorenin. These results suggest that active renin is processed in the kidney by a circulating enzyme that may have a role in the regulation of circulating renin.
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PMID:Rat renal and plasma prorenin are activated in vitro by different mechanisms. 1048 4

It was reported that Df-protease from house dust mite (Dermatophagoides farinae) catalyzes the activation of the kallikrein-kinin system in human plasma and is closely associated with mite-induced allergy. Therefore, to prevent the release of kinin by Df-protease, the inhibitory activity of polyphenols including catechins and flavonols was tested in vitro and in vivo. Among them, myricetin and epigallocatechin gallate (EGCg) effectively inhibited the amidase activity of Df-protease with K(i) values of 1 x 10(-)(8) and 6 x 10(-)(4) M, respectively. The kinin release in human plasma was extensively inhibited by the addition of EGCg in comparison with myricetin. Enhancement of vascular permeability in guinea pigs caused by Df-protease was markedly suppressed by EGCg.
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PMID:Inhibition of Df-protease associated with allergic diseases by polyphenol. 1055 95

We assessed a kallikrein-like amidase activity probably related to the kallikrein-kinin system, as well as the participation of leukocyte infiltration in renal ischemia and reperfusion. Male C57BL/KSJmdb mice were subjected to 20 or 60 min of ischemia and to different periods of reperfusion. A control group consisted of sham-operated mice, under similar conditions, except for ischemia induction. Kallikrein-like amidase activity, Evans blue extravasation and myeloperoxidase activity were measured in kidney homogenates, previously perfused with 0.9% NaCl. Plasma creatinine concentration increased only in the 60-min ischemic group. After 20 min of ischemia and 1 or 24 h of reperfusion, no change in kallikrein-like amidase activity or Evans blue extravasation was observed. In the mice subjected to 20 min of ischemia, edema was evident at 1 h of reperfusion, but kidney water content returned to basal levels after 24 h of reperfusion. In the 60-min ischemic group, kallikrein-like amidase activity and Evans blue extravasation showed a similar significant increase along reperfusion time. Kallikrein-like amidase activity increased from 4 nmol PNA mg protein-1 min-1 in the basal condition to 15 nmol PNA mg protein-1 min-1 at 10 h of reperfusion. For dye extravasation the concentration measured was near 200 microg of Evans blue/g dry tissue in the basal condition and 1750 microg of Evans blue/g dry tissue at 10 h of reperfusion. No variation could be detected in the control group. A significant increase from 5 to 40 units of DeltaAbs 655 nm g wet tissue-1 min-1 in the activity of the enzyme myeloperoxidase was observed in the 60-min ischemic group, when it was evaluated after 24 h of reperfusion. Histological analysis of the kidneys showed migration of polymorphonuclear leukocytes from the vascular bed to the interstitial tissue in the 60-min ischemic group after 24 h of reperfusion. We conclude that the duration of ischemia is critical for the development of damage during reperfusion and that the increase in renal cortex kallikrein-like amidase activity probably released from both the kidney and leukocytes may be responsible, at least in part, for the observed effects, probably through direct induction of increased vascular permeability.
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PMID:Kallikrein-like amidase activity in renal ischemia and reperfusion. 1077 92

Protein G columns were used to remove IgG from human plasma, and the effect on levels of factor XII, factor XI and prekallikrein was studied in functional tests. IgG was detected in PAGE immunoblot experiments with Fc-specific antibodies. Removal of the bulk of IgG in a procedure based on a low plasma dilution (1+2.5) allowed the passage of an IgG fraction along with the contact factors. This fraction was found to be present in higher amounts in plasma from patients with Crohn's disease (n=5) than in control plasma (n=12). In a previous study, PAGE immunoblot experiments showed that part of the prekallikrein was removed along with IgG when a higher plasma dilution (1+10.8) was used (Scand J Clin Lab Invest 1999; 59: 55-64). This observation was supported by results in the present work based on parallel assays with the peptide substrates S-2302 and Bz-Pro-Phe-Arg-pNA. The prekallikrein fraction removed was present in a functional state differing from the main part of prekallikrein by yielding kallikrein with a significantly increased activity against the substrate S-2366. This prekallikrein fraction was present in higher amounts in patient plasma than in control plasma. Part of the corresponding amidase activity was blocked by lima bean trypsin inhibitor, suggesting its presence in association with factor XI. The results also indicated that prekallikrein activator activity was connected with this fraction. With the high dilution procedure an extensive removal of IgG from the patient plasma was obtained compared to the control plasma.
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PMID:Removal of IgG from normal plasma and plasma from untreated patients with active Crohn's disease--effect on levels of contact factors. 1088 96


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