scholarly journals Insights into the regulation of the matriptase-prostasin proteolytic system

2020 ◽  
Vol 477 (22) ◽  
pp. 4349-4365
Author(s):  
Lasse Holt-Danborg ◽  
Signe Skovbjerg ◽  
Kristian W. Goderum ◽  
Annika W. Nonboe ◽  
Evelina Stankevic ◽  
...  

The membrane-associated prostasin and matriptase belonging to the S1A subfamily of serine proteases, are critical for epithelial development and maintenance. The two proteases are involved in the activation of each other and are both regulated by the protease inhibitors, HAI-1 and HAI-2. The S1A subfamily of serine proteases are generally produced as inactive zymogens requiring a cleavage event to obtain activity. However, contrary to the common case, the zymogen form of matriptase exhibits proteolytic activity, which can be inhibited by HAI-1 and HAI-2, as for the activated counterpart. We provide strong evidence that also prostasin exhibits proteolytic activity in its zymogen form. Furthermore, we show that the activity of zymogen prostasin can be inhibited by HAI-1 and HAI-2. We report that zymogen prostasin is capable of activating zymogen matriptase, but unable to activate its own zymogen form. We propose the existence of an unusual enzyme–enzyme relationship consisting of proteolytically active zymogen forms of both matriptase and prostasin, kept under control by HAI-1 and HAI-2, and located at the pinnacle of an important proteolytic pathway in epithelia. Perturbed balance in this proteolytic system is likely to cause rapid and efficient activation of matriptase by the dual action of zymogen matriptase and zymogen prostasin. Previous studies suggest that the zymogen form of matriptase performs the normal proteolytic functions of the protease, whereas excess matriptase activation likely causes carcinogenesis. HAI-1 and HAI-2 are thus important for the prevention of matriptase activation whether catalysed by zymogen/activated prostasin (this study) or zymogen/activated matriptase (previous studies).

2020 ◽  
Vol 23 (3) ◽  
pp. 350-358
Author(s):  
L. Kianifard ◽  
M. Yakhchali ◽  
M. Imani

This study was conducted to analyse the serine protease of Fasciola hepatica eggs by specific substrates and inhibitors, and investigation of the effects of pH and temperature on proteases’ activity and stability. Adult worms were isolated from infected livers. After homogenisation, their protein levels were measured with the Bradford method. Total proteolytic activity of the Fasciola hepatica extract was evaluated with azocasein substrate at pH values from 2 to 12. N-benzoyl–arginine–p-nitroanilide (BApNA) trypsin and N-succinyl-alanine-alanine-prolin-phenylalanine-p-nitroanilide (SAAPFpNA) chymotrypsin substrates were used to measure specific protease activities. The effect of protease inhibitors phenylmethane sulfonyl fluoride (PMSF), pepsin, and ethylenediaminetetraacetic acid (EDTA) on these enzymes was evaluated. Estimation of optimum temperature and pH was performed in the temperature range of 10–90 °C and pH values from 2–12. The optimum pH activities for trypsin and chymotrypsin were at alkaline pH and for total proteolytic activity at acidic pH. The results using protease inhibitors showed that the eggs had serine protease activity. The optimum temperature activity of trypsin and chymotrypsin was 50 °C. These proteases were stable up to 40 °C. Due to the importance of pH and temperature in life cycle of Fasciola hepatica, these findings can be used for induction of some modifications in pH and preventing the activity of the enzyme for decrement of the efficacy of embryonic development and egg hatching of this zoonotic parasite.


2021 ◽  
Vol 9 ◽  
Author(s):  
Timo Burster ◽  
Zhadyra Mustafa ◽  
Dinara Myrzakhmetova ◽  
Anuar Zhanapiya ◽  
Michal Zimecki

During inflammation neutrophils become activated and segregate neutrophil serine proteases (NSPs) to the surrounding environment in order to support a natural immune defense. However, an excess of proteolytic activity of NSPs can cause many complications, such as cardiovascular diseases and chronic inflammatory disorders, which will be elucidated on a biochemical and immunological level. The application of selective serine protease inhibitors is the logical consequence in the management of the indicated comorbidities and will be summarized in this briefing.


2020 ◽  
Vol 27 (11) ◽  
pp. 1159-1170
Author(s):  
Mohamed Azarkan ◽  
Mariana Marta González ◽  
Rafaèle Calvo Esposito ◽  
María Eugenia Errasti

Background: Antiplatelet, anticoagulant and fibrinolytic activities of stem bromelain (EC 3.4.22.4) are well described, but more studies are still required to clearly define its usefulness as an antithrombotic agent. Besides, although some effects of bromelain are linked to its proteolytic activity, few studies were performed taking into account this relationship. Objective: We aimed at comparing the effects of stem bromelain total extract (ET) and of its major proteolytic compounds on fibrinogen, fibrin, and blood coagulation considering the proteolytic activity. Methods: Proteolytic fractions chromatographically separated from ET (acidic bromelains, basic bromelains, and ananains) and their irreversibly inhibited counterparts were assayed. Effects on fibrinogen were electrophoretically and spectrophotometrically evaluated. Fibrinolytic activity was measured by the fibrin plate assay. The effect on blood coagulation was evaluated by the prothrombin time (PT) and activated partial thromboplastin time (APTT) tests. Effects were compared with those of thrombin and plasmin. Results: Acidic bromelains and ananains showed thrombin-type activity and low fibrinolytic activity, with acidic bromelains being the least effective as anticoagulants and fibrinolytics; while basic bromelains, without thrombin-like activity, were the best anticoagulant and fibrinolytic proteases present in ET. Procoagulant action was detected for ET and its proteolytic compounds by the APTT test at low concentrations. The measured effects were dependent on proteolytic activity. Conclusion: Two sub-populations of cysteine proteases exhibiting different effects on fibrin (ogen) and blood coagulation are present in ET. Using well characterized stem bromelain regarding its proteolytic system is a prerequisite for a better understanding of the mechanisms underlying the bromelain action.


2017 ◽  
Vol 61 (4) ◽  
Author(s):  
Samuel T. Cahill ◽  
Ricky Cain ◽  
David Y. Wang ◽  
Christopher T. Lohans ◽  
David W. Wareham ◽  
...  

ABSTRACT β-Lactamase-mediated resistance is a growing threat to the continued use of β-lactam antibiotics. The use of the β-lactam-based serine-β-lactamase (SBL) inhibitors clavulanic acid, sulbactam, and tazobactam and, more recently, the non-β-lactam inhibitor avibactam has extended the utility of β-lactams against bacterial infections demonstrating resistance via these enzymes. These molecules are, however, ineffective against the metallo-β-lactamases (MBLs), which catalyze their hydrolysis. To date, there are no clinically available metallo-β-lactamase inhibitors. Coproduction of MBLs and SBLs in resistant infections is thus of major clinical concern. The development of “dual-action” inhibitors, targeting both SBLs and MBLs, is of interest, but this is considered difficult to achieve due to the structural and mechanistic differences between the two enzyme classes. We recently reported evidence that cyclic boronates can inhibit both serine- and metallo-β-lactamases. Here we report that cyclic boronates are able to inhibit all four classes of β-lactamase, including the class A extended spectrum β-lactamase CTX-M-15, the class C enzyme AmpC from Pseudomonas aeruginosa, and class D OXA enzymes with carbapenem-hydrolyzing capabilities. We demonstrate that cyclic boronates can potentiate the use of β-lactams against Gram-negative clinical isolates expressing a variety of β-lactamases. Comparison of a crystal structure of a CTX-M-15:cyclic boronate complex with structures of cyclic boronates complexed with other β-lactamases reveals remarkable conservation of the small-molecule binding mode, supporting our proposal that these molecules work by mimicking the common tetrahedral anionic intermediate present in both serine- and metallo-β-lactamase catalysis.


Reproduction ◽  
2007 ◽  
Vol 134 (6) ◽  
pp. 721-729 ◽  
Author(s):  
Brigitte Le Magueresse-Battistoni

The testis is an organ in which a series of radical remodeling events occurs during development and in adult life. These events likely rely on a sophisticated network of proteases and complementary inhibitors, including the plasminogen activation system. This review summarizes our current knowledge on the testicular occurrence and expression pattern of members of the plasminogen activation system. The various predicted functions for these molecules in the establishment and maintenance of the testicular architecture and in the process of spermatogenesis are presented.


2012 ◽  
Vol 67 (9-10) ◽  
pp. 495-509 ◽  
Author(s):  
Juliana da Silva Pacheco ◽  
Raquel Elisa da Silva-Lopez

The characterization of legume proteases contributes to the understanding of the physiology of plants and their interaction with the environment. Thirteen extracts from various parts of Crotalaria spectabilis were made using different extraction systems. The highest protein content was found in seeds, and the most pronounced proteolytic activity was observed in leaf extracts, with an optimal pH value in the alkaline range. Proteases in extracts from roots, stems, and fl owers were active in various pH ranges. Proteases in all extracts were maximally active between 30 °C and 60 °C and were thermostable (24 h, 60 °C). Hemoglobin, bovine serum albumin, casein, and gelatin were hydrolyzed by C. spectabilis extracts in different ways. The highest serine protease activity was found in leaves. Seeds contained high levels of serine proteases and low levels of cysteine proteases. Flowers, roots, and stems contained different levels of serine, aspartic, and metalloproteases, respectively. The proteolytic activities in extracts were modulated by cations and oxidants to various degrees. C. spectabilis proteases are differentially expressed in distinctive organs, and their stability against heat and oxidants makes this plant an important source of stable proteases


Marine Drugs ◽  
2019 ◽  
Vol 17 (12) ◽  
pp. 701 ◽  
Author(s):  
Xingchen Chen ◽  
Darren Leahy ◽  
Jessica Van Haeften ◽  
Perry Hartfield ◽  
Peter J. Prentis ◽  
...  

Serine proteases play pivotal roles in normal physiology and a spectrum of patho-physiological processes. Accordingly, there is considerable interest in the discovery and design of potent serine protease inhibitors for therapeutic applications. This led to concerted efforts to discover versatile and robust molecular scaffolds for inhibitor design. This investigation is a bioprospecting study that aims to isolate and identify protease inhibitors from the cnidarian Actinia tenebrosa. The study isolated two Kunitz-type protease inhibitors with very similar sequences but quite divergent inhibitory potencies when assayed against bovine trypsin, chymostrypsin, and a selection of human sequence-related peptidases. Homology modeling and molecular dynamics simulations of these inhibitors in complex with their targets were carried out and, collectively, these methodologies enabled the definition of a versatile scaffold for inhibitor design. Thermal denaturation studies showed that the inhibitors were remarkably robust. To gain a fine-grained map of the residues responsible for this stability, we conducted in silico alanine scanning and quantified individual residue contributions to the inhibitor’s stability. Sequences of these inhibitors were then used to search for Kunitz homologs in an A. tenebrosa transcriptome library, resulting in the discovery of a further 14 related sequences. Consensus analysis of these variants identified a rich molecular diversity of Kunitz domains and expanded the palette of potential residue substitutions for rational inhibitor design using this domain.


Blood ◽  
1978 ◽  
Vol 52 (1) ◽  
pp. 1-12 ◽  
Author(s):  
N Aoki ◽  
K Naito ◽  
N Yoshida

Abstract The possible participation of proteases in human platelet aggregation was explored using various protease inhibitors and substrates. Protease inhibitors used included naturally occurring inhibitors of serine proteases and synthetic inhibitors that modify the active site of protease. Substrates used were synthetic substrates for the trypsin type as well as for the chymotrypsin type of protease. All these inhibitors and substrates inhibited platelet aggregation and serotonin release induced by ADP, collagen, epinephrine, or thrombin. In ADP- and epinephrine-induced platelet aggregation the second phase of aggregation was most efficiently inhibited. The inhibitors suppressed the formation of malondialdehyde during platelet aggregation. Release by aggregating agents of arachidonate and its metabolites from indomethacin-treated platelets as well as nontreated platelets was also inhibited. The inhibitors apperar to interact with stimulated platelets but not with unstimulated platelets. These observations suggest that the interaction of an aggregating agent with its platelet receptor activates a unique precursor serine protease that in turn activates platelet phospholipase to liberate arachidonic acid (the precursor of the potent platelet aggregating agent thromboxane A2) from platelet phospholipids.


1994 ◽  
Vol 40 (2) ◽  
pp. 106-112 ◽  
Author(s):  
Thomas Krarup ◽  
Lauritz W. Olson ◽  
Hans Peter Heldt-Hansen

The extracellular proteolytic enzymes of eight saprophytic, eucarpic, and monocentric isolates from two genera of the order Spizellomycetales and from one genus of the order Chytridiales (Chytridiomycetes) have been partially characterized. The isolectric points of the proteases were estimated from zymograms and demonstrate the existence of three types of proteolytic activity in most isolates. The proteases were tested against synthetic chromogenic peptide substrates and a selection of cations and more complex compounds, and the results suggest that parts of the extracellular proteolytic activities are due to proteases from two groups: the Ca2+ stabilized proteases and the alkaline serine proteases.Key words: serine proteases, metalloproteases, Chytridiomycetes, isoelectric focusing, chromogenic peptide substrates.


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