Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.21.7 (plasmin)
 9,023 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The extracts of granules of human polymorphonuclear leukocytes hydrolyzed a variety of proteins including human and bovine hemoglobin, human fibrinogen, human and bovine serum albumin, bovine elastin, and casein. The hydrolysis of all the proteins except fibrinogen and elastin was increased by addition of urea. Various inhibitors of trypsin, kallikrein, plasmin, Clr, Cls, and other proteolytic enzymes had no inhibitory effect. Slight inhibition was observed with polyanethol sulfonate and strong inhibition with normal human serum. Serum of patients with hereditary angioneurotic edema having no functional C1-esterase inhibitor was as effective in inhibiting the proteolysis as normal serum. The inhibitor was localized in 4S fractions of normal serum fractionated on Sephadex G-200. Fractionation of normal serum by ammonium sulfate precipitation, Sephadex G-200 filtration, and CM-Sephadex chromatography did not result in appearance of inhibitory activity in more than one protein peak, suggesting the possibility that only one inhibitor might be responsible. Since all fractions which contained the inhibitor of proteolysis also contained alpha1-antitrypsin, since sera of patients having low alpha1-antitrypsin levels contained less inhibitory activity, and since antibodies against alpha1-antitrypsin reversed the inhibition obtained from normal serum, the inhibition of proteolysis may be attributed to alpha1-antitrypsin.
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PMID:Some properties of proteolysis by polymorphonuclear leukocyte-granule extracts. 0 49

The function and several of the structural features of the C1 inactivator protein isolated from the plasma of a mother and daughter with the variant form of hereditary angioneurotic edema have been examined. These abnormal inhibitors shared immunologic identity with the normal C1 inactivator protein; however, they were inactive in inhibiting the functional activity of C1s. Analysis of the abnormal inhibitors by sodium dodecyl sulfate (SDS) acrylamide gel electrophoresis suggested that each consisted of a single polypeptide chain, the mobility of which was slower than that of the normal C1 inactivator. The apparent molecular weight of the patients' inhibitors was 109,000 daltons as contrasted to 105,000 daltons, that of the normal C1 inactivator. The abnormal inhibitors failed to form a complex with C1s or plasmin as analyzed by SDS-acrylamide gels. The large proteolytic derivatives resulting from the plasmin- and trypsin-induced degradation of the abnormal inhibitors were approximately 3,000 daltons heavier than the corresponding products derived from normal C1 inactivator. Thus, the structural abnormality identified appeared to be a property of the core molecule. Treatment of the inhibitors with neuraminidase failed to demonstrate a difference between the normal and patient-derived C1 inactivator molecule. Neither were major differences found between the amino acid composition of the defective and normal inhibitors; however, the acidic amino acids tended to be higher in the patients' inhibitors, and the phenylalanine content lower. Thus, these studies have identified both structural and functional abnormalities in the C1 inactivator protein isolated from two related patients with hereditary angioneurotic edema. Examination of the interaction between endopeptidases and the inhibitors has further delineated the abnormal structural features.
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PMID:Studies on human plasma C1 inactivator-enzyme interactions. II. Structural features of an abnormal C1 inactivator from a kindred with hereditary angioneurotic edema. 12 52

EDTA plasma from patients with hereditary angioedema (HAE), the genetic deficiency of C1-inhibitor, when incubated at 37 degrees produces a kinin-like activity which can induce contraction of oestrus rat uterus. The second component of complement (C2) has previously been suggested to be the source of this kinin-like activity, with the implication that C2-kinin is a normal product of complement activation. Our results show that purified human C2 is cleaved rapidly to C2a and C2b when added to HAE plasma, but not normal plasma or plasma from a danazol-treated HAE patient. However, the addition to HAE plasma of C2 at 20 X normal plasma concentration had no effect on the kinin activity generated on incubation at 37 degrees. In the presence of soya bean trypsin inhibitor, the rate of C2 cleavage and products were unaltered but no kinin activity was generated. C2 was cleaved by purified C1s to C2a and C2b. Incubation of C2 with trypsin resulted in cleavage to C2a and C2b followed by more extensive cleavage of both C2a and C2b. Kallikrein cleaved C2 to C2a and C2b but plasmin had no effect on C2. In no case was kinin activity generated. When C2 was cleaved by C1s to C2a and C2b then incubated with trypsin, kallikrein, or plasmin, no kinin activity was generated: only trypsin cleaved the C2 fragments further. The results suggest that C2 is not the source of the kinin-like activity generated in hereditary angioedema plasma.
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PMID:Cleavage of the second component of complement by plasma proteases: implications in hereditary C1-inhibitor deficiency. 293 17

The contact activation and fibrinolytic systems were assessed in 5 patients with hereditary angioedema (HAE). Reductions in F XII levels and increase in kallikrein-like activity in some patients indicated activation of the contact (intrinsic) system of coagulation. A great increase in plasmin-alpha 2-antiplasmin complex in all subjects indicated that in this disease, there is a constantly ongoing fibrinolysis. Since C1-inhibitor, the deficient protein in HAE, is a poor inhibitor of the well-known extrinsic (tissue-type) plasminogen activator, but the major inhibitor of the contact activation system and a related in vitro phenomenon termed intrinsic fibrinolysis, our data show that this fibrinolytic system is also sometimes operating efficiently in vivo. Furthermore, the known clinical data on HAE are compatible with a role of intrinsic fibrinolysis in the pathophysiology of this disease.
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PMID:Elevated plasmin-alpha 2-antiplasmin complex levels in hereditary angioedema: evidence for the in vivo efficiency of the intrinsic fibrinolytic system. 293 73

Isolated inherited deficiency states of almost every complement protein have been recognized. Almost all are autosomal recessive traits. Deficiency of the early-acting components C1, C4 and C2 is associated with increased risk of immune complex disease, particularly systemic lupus erythematosus. Patients with deficiency of C3, factor I or factor H have increased susceptibility to infection by pyogenic bacteria, whereas those with deficiencies of properdin, C5, C6, C7 or C8 are prone to systemic neisserial infection. Inherited deficiency of C1 inhibitor is transmitted as an autosomal dominant trait, is genetically heterogeneous, and is associated with attacks of angioedema and consumption of C4 and C2. There is evidence that a plasmin-modified fragment of C2 is responsible for the angioedema in this disorder. Administration of androgens tends to correct the biochemical abnormalities of hereditary angioedema and to prevent attacks.
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PMID:Inherited deficiencies of complement components in man. 357 Mar 60

C1(-)-inhibitor (C1(-)-INH) proteins from normal persons and members of eight different kindred with dysfunctional C1(-)-INH proteins associated with hereditary angioneurotic edema (HANE) were compared with respect to their inhibitory activity against purified preparations of C1s-, plasma kallikrein, activated forms of Hageman factor, and plasmin. Each dysfunctional C1(-)-INH protein showed a unique spectrum of inhibitory activity against these enzymes. Although none of the dysfunctional C1(-)-INH proteins significantly impaired amidolysis by plasmin, all but one inhibited activated Hageman factor. One purified dysfunctional C1(-)-INH (Ta) inhibited purified C1s- to a normal degree. Another C1(-)-INH (Za) had almost seven times as much inhibitory activity as normal C1(-)-INH against activated Hageman factor, but had decreased activity against C1s- and no activity against plasmin. Analyses of mixtures of plasmin and C1(-)-INH proteins in SDS gel electrophoresis revealed variability in the patterns of complex formation and cleavage of dysfunctional proteins after exposure to C1s- and plasmin. Some bound to plasmin and were cleaved, even though none significantly impaired the amidolytic activity of plasmin. Two were cleaved by C1s-, whereas neither normal or other dysfunctional C1(-)-INH were cleaved. Dysfunctional C1(-)-INH proteins from patients with HANE are thus heterogeneous in their inhibitory properties and there must be different structural requirements for the inhibition of the various plasma enzymes that can be regulated by normal C1(-)-INH. The data suggest that in addition to common sites of interactions between these proteases and C1(-)-INH, there are also points of contact that are specific for each protease. Genetic mutations leading to structural changes at some of these sites may have differing effects on the interaction between individual proteases and abnormal C1(-)-INH proteins. These alterations may allow these proteins to serve as probes for structural requirements for inhibitory actions of normal C1(-)-INH.
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PMID:Variability in purified dysfunctional C1(-)-inhibitor proteins from patients with hereditary angioneurotic edema. Functional and analytical gel studies. 396

Hereditary angioedema (HAE) is due to a functional deficiency of the inhibitor of the activated first component of complement (C1 INH). This abnormality is thought to be responsible for the generation of a kininlike peptide in HAE plasma that is derived from the second component of complement (C2). Specifically, a combination of C2 cleavage by C1s and C2 fragment cleavage by plasmin has been reported to generate a kinin that is distinguishable from bradykinin. We have attempted to generate this peptide by activating the classical complement pathway by incubation of plasma with immune complexes and then adding plasmin or by incubating purified C1s with C4 and C2 and then adding either plasmin or trypsin. We performed a total of 13 experiments, and in no case was a kininlike molecule generated as assessed by contraction of the estrus rat uterus. However, incubation of EDTA-treated HAE plasma at 37 degrees C for time intervals up to 1 hr progressively generated a smooth muscle-contracting activity. This activity was resistant to tryptic digestion but was destroyed after incubation with carboxypeptidase B, an inhibition profile consistent with that of bradykinin. We therefore propose that bradykinin alone, or in combination with other factors heretofore unrecognized, might be responsible for the swelling that is characteristic of hereditary angioedema.
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PMID:Kinin formation in hereditary angioedema plasma: evidence against kinin derivation from C2 and in support of "spontaneous" formation of bradykinin. 622 4

This clinical entity described for the first time by Osler in 1888 presented a great therapeutic problem during many decades because of its severity. Landerman and later on Donaldson and Evans established the pathogenic mechanisms of this disease finding a deficiency in the inhibitor of the first activated component of complement, an alpha 2 aminoglycoprotein, to be the mechanism responsible of the same. More concretely, alterations in the plasmin, kinin and kallikrein systems are those that will lead to a change in vascular permeability with resultant tissue alterations. Four cases of hereditary angioneurotic edema are studied in female patients aged between 15 and 50 years and with family history consistent with angioneurotic familiar edema in which there were six cases of death due to edema of the glottis. Once the diagnosis had been made the patients were subjected to treatment with EACA at doses of 2.5 gm every 6 hours. The determinations of complement were similar in the four cases, with marked decreases in C4 and C1 inhibitor with a decrease in total complement in three cases. Regarding secondary effects, vomiting was found only in one cases, which as the dose was reduced did not necessitate termination of treatment. In summary, considering the results obtained in the cases above, we believe that due to its good tolerance and moderate cost, epsilon-amino-caproic acid at the abovementioned dosage is an excellent pharmacological agent in the treatment of Osler's hereditary angioneurotic edema.
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PMID:Epsilon-amino-caproic acid in the treatment of Osler's hereditary angioneurotic edema. 685 4

C1-inhibitor deficiency results in bouts of mucocutaneous edema and may be inherited (hereditary angioedema) or acquired (acquired angioedema [AAE]). The two forms have the same clinical picture but differ in the response to treatment. Prophylaxis with antifibrinolytic agents produces better results in the acquired form than in the inherited form, in which androgen derivatives are more effective. It is hypothesized that activation of the contact and fibrinolytic systems is involved in the pathogenesis of attacks. We evaluated these two systems in plasma from eight patients with AAE and anti-C1-inhibitor autoantibodies (autoimmune AAE) by measuring the cleavage of high molecular weight kininogen and the complexes formed by plasmin and its inhibitor alpha 2-antiplasmin. We also measured complement parameters, autoantibody titer, and cleaved C1-inhibitor (relative molecular mass = 96,000), because autoantibodies to C1-inhibitor are known to facilitate its cleavage by proteases. Plasma was obtained from patients in remission, during prophylactic treatment with the antifibrinolytic agent tranexamic acid (2 to 4.5 gm/day) and also from two patients during acute attacks of edema. Levels of cleaved high molecular weight kininogen and antiplasmin-plasmin complexes in patients with AAE were both higher in basal conditions, during treatment, and during acute attacks than those in normal subjects (p < 0.001). The cleaved inactive form of C1-inhibitor was also present in all patients in all three conditions. Therapy with antifibrinolytic agents reduced the frequency and intensity of symptoms without significantly changing any of the biochemical parameters.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Activation of the contact system and fibrinolysis in autoimmune acquired angioedema: a rationale for prophylactic use of tranexamic acid. 818 30

The biosynthesis of the serpin alpha 1-proteinase inhibitor is regulated by a feedback mechanism whereby complexes between alpha 1-proteinase inhibitor and serine proteinases bind to liver cells and monocytes, a reaction that activates alpha 1-proteinase-inhibitor gene transcription. Such a mechanism may form the basis for the development of new therapeutic strategies for serpin deficiency states with reduced levels of otherwise normally functioning serpins. This issue was addressed for C1-inhibitor, the missing serpin in hereditary angioedema. C1-inhibitor biosynthesis by Hep G2 hepatoma cells was assessed by enzyme-linked immunosorbant assay, by metabolic labeling followed by immunoprecipitation, and by Northern blotting. C1-inhibitor biosynthesis was stimulated by gamma-interferon (100 U/mL) but not by cell exposure to C1-inhibitor-kallikrein (1 mumol/L), C1-inhibitor-C1s (1 mumol/L), and C1-inhibitor-plasmin complexes (1 mumol/L) or to reactive site-cleaved C1-inhibitor (1 mumol/L). Moreover, radioiodinated C1s-C1-inhibitor complex did not bind to Hep G2 cells. C1-inhibitor-kallikrein complex was also without effect on C1-inhibitor mRNA in U 937 cells. Therefore, the proposed mechanism, by which serpin-enzyme complex or reactive site-cleaved serpin binding to a specific receptor provides a signal for the stimulation of the biosynthesis of that serpin, is not operative for the biosynthesis of C1-inhibitor by Hep G2 or U 937 cells.
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PMID:C1-inhibitor-serine proteinase complexes and the biosynthesis of C1-inhibitor by Hep G2 and U 937 cells. 824 7


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