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:3.4.21.4 (trypsin)
42,187 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

alpha 2-Antiplasmin (alpha 2-AP) is a major fibrinolysis inhibitor, whose complete, congenital absence has been found to be associated with a distinct hemorrhagic diathesis. We studied a 15-yr-old male with a hemorrhagic diathesis after trauma from early childhood on. This bleeding tendency was associated with a minimal alpha 2-AP level recorded functionally in the immediate plasmin inhibition test: less than or equal to 4% of normal. However, a normal plasma concentration of alpha 2-AP antigen (83%) was found. His sister (5 yr old) showed similar results (2 and 92%). In their family, eight heterozygotes could be identified by half-normal activity results and normal antigen concentrations. The inheritance pattern is autosomal recessive. On analysis, the alpha 2-AP of the propositus was homogeneous in all respects tested, suggesting a homozygous defect. We designated the abnormal alpha 2-AP as alpha 2-AP Enschede. alpha 2-AP Enschede showed the following characteristics: (a) complete immunological identity with normal alpha 2-AP; (b) normal molecular weight (sodium dodecyl sulfate-polyacrylamide gel electrophoresis); (c) normal alpha-electrophoretic mobility; (d) presence in plasma of both molecular forms excluding an excessive conversion to the less reactive non-plasminogen-binding form; (e) quantitatively normal binding to lys-plasminogen and to immobilized plasminogen kringle 1-3; and (f) normal Factor XIII-mediated binding to fibrin. Functional abnormalities were found in: (i) no inhibition of amidolytic activities of plasmin and trypsin, even on prolonged incubation; (ii) no formation of plasmin-antiplasmin complexes in plasma with plasmin added in excess; and (iii) no inhibition of fibrinolysis by fibrin-bound alpha 2-AP. In the heterozygotes, the presence of abnormal alpha 2-AP did not interfere with several functions of the residual normal alpha 2-AP. One-dimensional peptide mapping showed an abnormal pattern of papain digestion. We conclude that in this family, abnormal antiplasmin molecules, defective in plasmin inhibition but with normal plasminogen-binding properties, have been inherited. The residual plasminogen-binding properties do not protect against a hemorrhagic diathesis.
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PMID:alpha 2-Antiplasmin Enschede: dysfunctional alpha 2-antiplasmin molecule associated with an autosomal recessive hemorrhagic disorder. 244 79

We present a cascade of proteolytic events catalyzed by the proteases secreted by cultured keratinocytes and fibroblasts that results in the activation of interstitial procollagenase. Cultured human skin fibroblasts constitutively secrete interstitial collagenase and stromelysin as proenzymes. In contrast, interstitial collagenase found in serum-free skin organ culture conditioned medium is activated. Cocultivation of the major cellular components of skin organ culture, dermal fibroblasts and epidermal keratinocytes, induces activation of interstitial procollagenase and prostromelysin in the presence of plasminogen. This activation occurs through a urokinase-dependent pathway where added keratinocytes secrete the plasminogen activator urokinase, which converts plasminogen into plasmin. Plasmin is capable of activating purified procollagenase and prostromelysin. Plasmin-dependent activation of procollagenase generates an enzyme species, by amino-terminal processing, identical to those generated by limited proteolysis with trypsin or treatment with organomercurial compounds. Catalytic amounts of activated stromelysin can in turn convert plasmin- or trypsin-activated collagenase into a fully active enzyme by removal of approximately 15 amino acid residues from the carboxyl end of the enzyme. This results in a 5- to 8-fold increase in collagenase specific activity that is due to its proteolytic cleavage and not to the presence of the activator stromelysin. Stromelysin alone in both pro- and activated forms is not capable of efficient activation of human fibroblast interstitial procollagenase.
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PMID:Tissue cooperation in a proteolytic cascade activating human interstitial collagenase. 246 56

The amidolytic steady-state kinetic properties of a series of recombinant tissue plasminogen activators (rt-PA) have been examined in the presence and absence of the positive effectors fibrinogen (Fg) and native soluble (des-A)-fibrin (sFn). Two-chain (tc) native rt-PA displayed a Km value of 0.50 mM and a kcat value of 13.2 s-1 toward the substrate, H-D-Ile-Pro-Arg-p-nitroanilide (S2288) at 37 degrees. When these same assays were conducted in the presence of Fg or sFn, the Km and kcat values remained essentially the same. On the other hand, the activity of single-chain (sc) rt-PA was significantly increased in the presence of Fg or sFn, by approximately 3.4- to 4-fold, due to alterations in both the Km and kcat of the reaction. Similar results were obtained with rt-PA deletion variants, obtained by site-directed mutagenesis. With rt-PA domain-deletion derivatives, consisting of kringles 1 (K1)-2 (K2)-protease (P), and K2-P, the amidolytic activities of the scrt-PA preparations were significantly stimulated (2.0- to 2.5-fold) by Fg and sFn, a property not shared by the corresponding tcrt-PA. On the other hand, neither the single- nor two-chain derivatives of a deletion mutant containing only the finger (F)-growth factor (E)-P domains displayed stimulation by Fg or sFn, results suggestive of the importance of the K2 region in the observed Fg- and Fn-induced stimulations rt-PA amidolytic activity. With one strategically important derivative, a molecule containing the amino acid replacement, Cys264----Gly [(Cys264----Gly)-rt-PA], a change resulting in the loss of covalent attachment of the heavy and light chains of tcrt-PA, the amidolytic activities of neither the single-chain nor the two-chain form of the molecule were stimulated by the presence of the above two positive effectors. With the single-chain form of this same derivative, the kcat of the reaction was extremely low (1.5 s-1), but increased to approximately 50.5 s-1 for the two-chain form, this latter value being nearly 4-fold higher than that of any of the wild-type recombinant rt-PA preparations examined. This suggests that the latent heavy chain of rt-PA inhibits the amidolytic activity found in the trypsin-like P domain.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Stimulation by fibrinogen of the amidolytic activity of single-chain tissue plasminogen activator. 249 44

Tissue-type plasminogen activator (t-PA) converts the inactive zymogen, plasminogen, into the powerful protease, plasmin, which then degrades the fibrin meshwork of thrombi. To prevent systemic activation of plasminogen, plasma contains several inhibitors of t-PA, the most important of which is plasminogen activator inhibitor-1 (PAI-1), a member of the serpin superfamily. As the ability to produce serpin-resistant variants of t-PA could increase the potential of this enzyme as a thrombolytic agent, we have used the known three-dimensional structure of the complex between trypsin and bovine pancreatic trypsin inhibitor (BPTI) to model the interactions between the active site of human t-PA and PAI-1. On the basis of this model we then altered by site-directed mutagenesis those amino acids of t-PA predicted to make contact with PAI-1 but not with the substrate plasminogen. We report here that although the resulting mutants have enzymatic properties similar to those of wild-type t-PA, they display significant resistance to inhibition by PAI-1. For example, following incubation with an amount of the serpin that completely inhibits the wild-type enzyme, one variant retains 95% of its initial activity. This mutant is also resistant to inhibition by the complex mixture of serpins present in human plasma.
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PMID:Serpin-resistant mutants of human tissue-type plasminogen activator. 250 May 99

alpha 2-Antiplasmin (alpha 2AP), a serpin proteinase inhibitor with two methionine residues in its reactive center, was treated with cis-dichlorodiammineplatinum (II) (cis-DDP). This compound has been utilized previously to specifically modify methionine residues. After reaction, the alpha 2AP demonstrated decreased inhibitory activity against plasmin, miniplasmin, trypsin and chymotrypsin. The reduction in activity depended on the concentration of cis-DDP; however, the amount of activity retained by the treated alpha 2AP was equivalent with each of the four proteinases. alpha 2AP that was incubated with 1.0 mM cis-DDP for 3 h at 37 degrees C was 90% inactivated. These same conditions resulted in the binding of only 1.0-1.5 mol of platinum per mol of inhibitor. In experiments with lower concentrations of cis-DDP, the amount of incorporated platinum directly correlated with the amount of inactivated alpha 2AP (1:1 stoichiometry). Reactions and functions of alpha 2AP that do not result in proteinase inhibition were not affected by cis-DDP. Cleavage of alpha 2AP by elastase, which occurs near the proteinase inhibition site, was unaffected. In addition, the affinity of alpha 2AP for the K1-3 region of plasminogen remained unchanged after treatment. These data strongly suggest that the reaction of alpha 2AP with cis-DDP involves principally a single site on the inhibitor and that this site is critical for proteinase inhibitory activity. The most likely candidate is the P'1 methionine which is adjacent to the peptide bonds cleaved in the proteinase inhibitory reactions but not in the elastase reaction.
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PMID:Inactivation of alpha 2-antiplasmin by limited reaction with cis-dichlorodiammineplatinum (II) 252 Dec 1

Plasminogen activator activity was determined in human follicular fluids (FFs) obtained during in vitro fertilization procedures. The fibrinolytic activity of plasminogen activator was significantly higher in fluids from follicles that contained oocytes that were later found to fertilize in vitro (group F) as compared with fluids from follicles that contained oocytes that failed to fertilize (NF). To assess whether this difference in overt plasminogen activator activity reflects differences in conversion of an inactive, latent plasminogen activator to the active enzyme, the ability of exogenous trypsin to enhance plasminogen activation was measured. The plasminogen-dependent hydrolysis of the chromogenic substrate S-2444 in presence of trasylol (Bayer, Leverkusen, Germany) was taken as a measure of plasminogen activator activity in these experiments. No activity was found in untreated FFs, while exposure to trypsin resulted in emergence of marked plasminogen activator activity. In addition, FFs exhibited trasylol-sensitive chromogenic activity indicative of serine-protease activity. Both the plasminogen activator and serine-protease levels after tryptic activation were significantly higher in NF than in F samples. Thus, while F samples have most of their plasminogen activator in an active form, NF samples have most of their plasminogen activator in a latent, trypsin-activatable form. Follicular fluids also contain inhibitory activities toward plasmin and trypsin. The inhibition of these enzymes correlates positively with the latency of plasminogen activator. These results suggest a direct relationship between the ability of oocytes to fertilize and the overt to latent plasminogen activator activity ratios in the FFs.
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PMID:Human follicular fluid protease and antiprotease activities: a suggested correlation with ability of oocytes to undergo in vitro fertilization. 252 54

The effect of human skin mast cell tryptase on human plasma proenzymes (prothrombin, coagulation factor XII, complement C1s, protein C and plasminogen) was investigated. Tryptase had no effect on these proenzymes, when incubated with them at 37 degrees C for up to 90 min, as judged by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and by the ability to hydrolyze specific peptide p-nitroanilide substrates. After prolonged treatment with tryptase, proenzymes could be fully activated with their specific activators. The results indicate that tryptase neither activates these plasma proenzymes nor inactivates the corresponding active enzymes. As a positive control, the tryptase preparation was also incubated with human fibrinogen and rat thymus histones. Prolonged treatment with tryptase increased the thrombin-induced clotting time of fibrinogen. Tryptase also efficiently hydrolyzed histone H1 from rat thymus. Histones H3/H2B and H2A were hydrolyzed less efficiently than H1, and no hydrolysis of histone H4 by tryptase was detected under the experimental conditions.
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PMID:Effect of human mast cell tryptase on human plasma proenzymes. 253 Jan 78

The activity of milk plasmin, plasminogen and N-acetyl-beta-glucosaminidase (NAGase) and the trypsin-inhibitor capacity (TIC) were monitored in 40 quarters during the first month of lactation. TIC and NAGase activity decreased rapidly and plasmin activity more slowly during the first week. Conversely milk plasminogen increased as time elapsed from parturition. When the quality of whey was analysed as a growth medium for mastitis pathogens, a slight inhibition in the growth of Escherichia coli, Staphylococcus aureus and Streptococcus agalactiae was seen at the day of parturition. There was a distinct stimulatory effect on the growth of Str. agalactiae during the second week of lactation. No relationship was found between in vitro bacterial growth and respective plasmin or plasminogen activity in milk.
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PMID:Changes in milk plasminogen, plasmin and in vitro bacterial growth in whey during early lactation. 253 63

The therapy with thymus extracts, oral and parenteral, reduced the frequency and the intensity of recurrences of herpes labialis infections. The duration of the effect was at least 6 month after interruption of the therapy. Indomethacin was effective and developed and intensive effect only during the therapy. The skin test with recall-antigens and the neopterin-elimination were altered at the first day of the menstruation during the recurrence. The normalisation succeeded during therapy. In patients with recurrences in the perimenstrual time we observed a reduced T-helper/T-suppressor index during the first day of menstruation. Normal data were registered out of the recurrence time and/or under therapy. Inhibitors of the lymphokine: leucocyte/migration inhibitory factor (LIF) with a molecular weight of 6-12 KD were obtained with the specific stimulation of mononuclear cells of patients with recurrent infections with herpes labialis using the herpes-virus-1 antigen. The inhibition of fibrinolysis/proteolysis with aprotinin, tranexamic acid, phenyl-methyl-sulphonyl-fluoride and di-isopropyl-fluorophosphate could prevent the appearance of inhibitors. Inhibitors could be produced by splitting the LIF-molecule with urokinase and plasminogen but not with trypsin. The production, but not the activity, of present LIF-inhibitors are blocked in vivo and in vitro by indomethacin and thymus peptides.
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PMID:[Recurrent herpes labialis infections: cellular immunity and immunomodulation]. 253 31

The specific role of proteolytic enzymes in the degradation by live cells of fibrillar model matrices (fibrin, collagen) was studied using monoclonal and polyclonal inhibitory (anti-catalytic) antibodies. Dissolution of fibrin by plasminogen-supplemented human HT-1080 cells was blocked by (1) omission of plasminogen, (2) inhibitory anti-plasmin antibody, and (3) inhibitory anti-u-PA antibody but not by non-inhibitory control antibodies. Using a similar approach, it was shown that the dissolution of reconstituted type I collagen fibrils by trypsin-supplemented live human skin fibroblasts was blocked by inhibitory antibodies to fibroblast-type procollagenase but not by noninhibitory control antibodies. These findings permit us to deduce that, at least in culture, the dissolution of fibrin by plasminogen-supplemented HT-1080 cells was mediated by plasminogen-assisted proteolysis which entailed the extracellular conversion of plasminogen to plasmin by cell-derived u-PA, and that the dissolution of collagen fibrils by trypsin-supplemented skin fibroblasts was mediated by a collagenase-dependent pathway.
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PMID:Use of inhibitory (anti-catalytic) antibodies to study extracellular proteolysis. 254 25


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