scholarly journals Negative selectivity and the evolution of protease cascades: the specificity of plasmin for peptide and protein substrates

2000 ◽  
Vol 7 (6) ◽  
pp. 443-452 ◽  
Author(s):  
Laurence S Hervio ◽  
Gary S Coombs ◽  
Robert C Bergstrom ◽  
Kavita Trivedi ◽  
David R Corey ◽  
...  
Keyword(s):  
Protein Substrates

Effect of Thrombin on Phosphorylation of Platelet Membrane Proteins

1976 ◽  
Vol 35 (03) ◽  
pp. 635-642 ◽  
Author(s):  
M Steiner
Keyword(s):  
Protein Kinase ◽  
Kinase Activity ◽  
Qualitative Change ◽  
Protein Kinase Activity ◽  
Protein Substrates ◽  
Phosphoprotein Phosphatase ◽  
Progressive Loss ◽  
Platelet Membranes ◽  
Endogenous Protein ◽  
Considerable Loss

SummaryThe effect of thrombin on the phosphorylating activity of platelet membranes was compared to that of trypsin. Preincubation of non-32P phosphorylated platelet membranes with or without either of these two enzymes resulted in a considerable loss of membrane protein kinase activity which was most severe when trypsin was used. Protein kinase activity and endogenous protein acceptors decreased in parallel. 32P-phosphorylated membranes showed a slow but progressive loss of label which was accelerated by trypsin. Thrombin under these conditions prevented the loss of 32P-phosphate. These results are interpreted to indicate a thrombin-induced destruction of a phosphoprotein phosphatase. The protein kinase activity of phosphorylated platelet membranes using endogenous or exogenous protein substrates showed a significant reduction compared to non-phosphorylated membranes suggesting a deactivation of protein kinase by phosphorylation of platelet membranes. Neither thrombin nor trypsin caused a qualitative change in the membrane polypeptides accepting 32P-phosphate but resulted in quantitative alterations of their ability to become phosphorylated.

scholarly journals The Gut-Brain Axis in Autism Spectrum Disorder: A Focus on the Metalloproteases ADAM10 and ADAM17

2020 ◽  
Vol 22 (1) ◽  
pp. 118
Author(s):  
Yuanpeng Zheng ◽  
Tessa A. Verhoeff ◽  
Paula Perez Pardo ◽  
Johan Garssen ◽  
Aletta D. Kraneveld
Keyword(s):  
Autism Spectrum Disorder ◽  
Intestinal Tract ◽  
Synapse Formation ◽  
Inflammatory Responses ◽  
Repetitive Behavior ◽  
Autism Spectrum ◽  
Spectrum Disorder ◽  
Protein Substrates ◽  
Specific Proteins ◽  
Membrane Bound

Autism Spectrum Disorder (ASD) is a spectrum of disorders that are characterized by problems in social interaction and repetitive behavior. The disease is thought to develop from changes in brain development at an early age, although the exact mechanisms are not known yet. In addition, a significant number of people with ASD develop problems in the intestinal tract. A Disintegrin And Metalloproteases (ADAMs) include a group of enzymes that are able to cleave membrane-bound proteins. ADAM10 and ADAM17 are two members of this family that are able to cleave protein substrates involved in ASD pathogenesis, such as specific proteins important for synapse formation, axon signaling and neuroinflammation. All these pathological mechanisms are involved in ASD. Besides the brain, ADAM10 and ADAM17 are also highly expressed in the intestines. ADAM10 and ADAM17 have implications in pathways that regulate gut permeability, homeostasis and inflammation. These metalloproteases might be involved in microbiota-gut–brain axis interactions in ASD through the regulation of immune and inflammatory responses in the intestinal tract. In this review, the potential roles of ADAM10 and ADAM17 in the pathology of ASD and as targets for new therapies will be discussed, with a focus on the gut–brain axis.

scholarly journals Factor XIII-A: An Indispensable “Factor” in Haemostasis and Wound Healing

2021 ◽  
Vol 22 (6) ◽  
pp. 3055
Author(s):  
Fahad S. M. Alshehri ◽  
Claire S. Whyte ◽  
Nicola J. Mutch
Keyword(s):  
Bone Marrow ◽  
Wound Healing ◽  
Crucial Role ◽  
Factor Xiii ◽  
Severe Bleeding ◽  
Bleeding Diathesis ◽  
Unknown Mechanism ◽  
Protein Substrates ◽  
Physiological Processes ◽  
Isopeptide Bonds

Factor XIII (FXIII) is a transglutaminase enzyme that catalyses the formation of ε-(γ-glutamyl)lysyl isopeptide bonds into protein substrates. The plasma form, FXIIIA2B2, has an established function in haemostasis, with fibrin being its principal substrate. A deficiency in FXIII manifests as a severe bleeding diathesis emphasising its crucial role in this pathway. The FXIII-A gene (F13A1) is expressed in cells of bone marrow and mesenchymal lineage. The cellular form, a homodimer of the A subunits denoted FXIII-A, was perceived to remain intracellular, due to the lack of a classical signal peptide for its release. It is now apparent that FXIII-A can be externalised from cells, by an as yet unknown mechanism. Thus, three pools of FXIII-A exist within the circulation: plasma where it circulates in complex with the inhibitory FXIII-B subunits, and the cellular form encased within platelets and monocytes/macrophages. The abundance of this transglutaminase in different forms and locations in the vasculature reflect the complex and crucial roles of this enzyme in physiological processes. Herein, we examine the significance of these pools of FXIII-A in different settings and the evidence to date to support their function in haemostasis and wound healing.

scholarly journals FURTHER STUDIES ON THE ROLE OF PROTEASES IN THE ALLERGIC REACTION

1961 ◽  
Vol 113 (2) ◽  
pp. 359-380 ◽  
Author(s):  
Georges Ungar ◽  
Takuso Yamura ◽  
Jacqueline B. Isola ◽  
Sidney Kobrin
Keyword(s):  
Amino Acid ◽  
Guinea Pig ◽  
Proteolytic Activity ◽  
Guinea Pigs ◽  
Protease Activity ◽  
Amino Acid Esters ◽  
Protein Substrates ◽  
Protease Activation ◽  
Acid Esters

Protease activity was measured through the hydrolysis of synthetic amino acid esters in body fluids and tissues of guinea pigs, rats, mice, and humans. Significant in vitro activation was observed in serum and lung slices of sensitized guinea pigs on addition of the specific antigen. Increased proteolytic activity was also seen in reverse anaphylaxis. More marked activation occurred when guinea pig serum was treated with peptone and guinea pig or rat serum was treated with agar. Protease activation was demonstrated in specimens of human skin under the influence of a poison ivy extract or croton oil added in vitro. Urinary protease activity of guinea pigs increased significantly during the first hours of anaphylactic shock and very markedly in peptone shock. Peptone shock, elicited in mice pretreated with H. pertussis, was accompanied by a considerable increase in protease activity in the peritoneal fluid as compared with non-pretreated mice which were insensitive to peptone. Proteolytic activity resulting from the activation procedures was due to a number of proteases. The dominant substrate affinity and inhibition patterns suggest that serum and urine proteases are similar to but not identical with plasmin. Anaphylactic activation exhibited patterns different from those resulting from the action of anaphylactoid agents. Tissue enzymes are either of cathepsin- or chymotrypsin-type or mixtures of both. Some of the activated enzymes, although remarkably effective in hydrolyzing amino acid esters, show no activity on protein substrates. This does not justify, however, their designation as "esterases." They probably belong to the class of specific proteases acting only on a single or a small number of functionally significant protein substrates. There is at present sufficient evidence to prove not only that protease activation does occur in anaphylaxis and anaphylactoid conditions but also that it is an important component of the chain of reactions leading to the allergic response.

Biochemical characterization of human HIF hydroxylases using HIF protein substrates that contain all three hydroxylation sites

2011 ◽  
Vol 436 (2) ◽  
pp. 363-369 ◽  
Author(s):  
Melissa B. Pappalardi ◽  
Dean E. McNulty ◽  
John D. Martin ◽  
Kelly E. Fisher ◽  
Yong Jiang ◽  
...  
Keyword(s):  
Biochemical Characterization ◽  
Hypoxia Inducible Factor ◽  
Prolyl Hydroxylase ◽  
Transactivation Domain ◽  
Prolyl Hydroxylases ◽  
Proline Residue ◽  
Protein Substrates ◽  
Steady State Kinetic ◽  
Asparaginyl Hydroxylase

The HIF (hypoxia-inducible factor) plays a central regulatory role in oxygen homoeostasis. HIF proteins are regulated by three Fe(II)- and α-KG (α-ketoglutarate)-dependent prolyl hydroxylase enzymes [PHD (prolyl hydroxylase domain) isoenzymes 1–3 or PHD1, PHD2 and PHD3] and one asparaginyl hydroxylase [FIH (factor inhibiting HIF)]. The prolyl hydroxylases control the abundance of HIF through oxygen-dependent hydroxylation of specific proline residues in HIF proteins, triggering subsequent ubiquitination and proteasomal degradation. FIH inhibits the HIF transcription activation through asparagine hydroxylation. Understanding the precise roles and regulation of these four Fe(II)- and α-KG-dependent hydroxylases is of great importance. In the present paper, we report the biochemical characterization of the first HIF protein substrates that contain the CODDD (C-terminal oxygen-dependent degradation domain), the NODDD (N-terminal oxygen-dependent degradation domain) and the CAD (C-terminal transactivation domain). Using LC-MS/MS (liquid chromatography–tandem MS) detection, we show that all three PHD isoenzymes have a strong preference for hydroxylation of the CODDD proline residue over the NODDD proline residue and the preference is observed for both HIF1α and HIF2α protein substrates. In addition, steady-state kinetic analyses show differential substrate selectivity for HIF and α-KG in reference to the three PHD isoforms and FIH.

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