Glutaminyl Residues Research Articles

Purification of bovine liver transglutaminase by gel filtration

Transglutaminases (TGases) are enzymes that catalyze transfer of acyl group and covalent crosslinks formation between peptide-bound glutaminyl residues and amino groups. TGases have many industrial applications and have been purified from various sources. TGase was purified from the bovine liver extract by gel filtration on Sephacryl S-200 HR column. TGase activity was measured using CBZ-l-glutaminylglycine & hydroxylamine and the enzyme was characterized with respect to its response to different temperatures, pHs and salt concentrations. TGase was purified by yield 36.7%, had a weight 74 kDa, a high pH (pH = 8) and temperature (45 °C) optimum. The enzyme was observed to be stable at temperatures below 55 °C and was stable within a narrow pH range of 6.5–8.0. Purified TGase showed Ca2+ dependent characteristics and tended to retain activity at a high NaCl concentration. These results revealed that purified TGase can be used as a potential alternative to other sources.

The Influences of transglutaminase enzyme dosage on the meat characteristic from restructuring the animal and vegetable protein sources

Transglutaminase (EC 2.3.2.13) catalyses an acyl-transfer reaction in which the γ-carboxamide group of peptide-bound glutaminyl residues are the acyl donors. In this research is compare the influence of transglutaminase enzyme dosage on the animal protein which is duck meat and vegetable protein which is analog meat from TSP and soy powder. The sample was tested by some instrument analysis namely pH meter, Texture Profile Analyzer (TPA). Then, the sample was analized its nutrition by Proximate test. By these tests, it could be obtained the optimum of amount transgluminase dosage in animal or vegetable protein source. The experimental variations is the enzyme dosage. The enzyme dosage for animal protein source are 0.0%; 0.3%; 0.6% and 1%, while vegetable protein source are 0.0%; 0.5%; 1,0%; 1.5% and 2% with the duration of 24 h incubation in 4°C. The result showed that the characteristic of each sample observed, increased dosage of transglutaminase enzyme affects the texture of sample as evedenced by TPA. In animal protein the optimum enzyme used is 0,6 %, while in vegetable protein the optimum enzyme is 1,5% as evedenced by TPA and acidity test level.

Possible roles of transglutaminases in molecular mechanisms responsible for cancer and human neurodegenerative diseases

Transglutaminases are a family of Ca2+- dependent enzymes which catalyze posttranslational modifications of proteins. The main activity of these enzymes is the crosslinking of glutaminyl residues of a protein/peptide substrate to lysyl residues of a protein/peptide co-substrate. In addition to lysyl residues, other second nucleophilic co-substrates may include monoamines or polyamines (to form mono- or bi-substituted/ crosslinked adducts) or -OH groups (to form ester linkages). In absence of co-substrates, the nucleophile may be water, resulting in the net deamidation of the glutaminyl residue. Transglutaminase activity has been suggested to be involved in molecular mechanisms responsible for either physiological or pathological processes. In particular, transglutaminase activity has been shown to be responsible for human autoimmune diseases and Celiac Disease is just one of them. Interestingly, cancer and neurodegenerative diseases, such as Alzheimer’s Disease, Parkinson’s Disease, supranuclear palsy and Huntington’s Disease, are characterized in part by aberrant transglutaminase activity and by increased cross-linked proteins in affected tissues. This review describes the possible molecular mechanisms by which these enzymes could be responsible for such diseases and the possible use of transglutaminase inhibitors for patients with diseases characterized by aberrant transglutaminase activity.

Transglutaminase inhibition: possible therapeutic mechanisms to protect cells from death in neurological disorders

Transglutaminases are a family of Ca²⁺-dependent enzymes which catalyze post-translational modifications of proteins. The main activity of these enzymes is the cross-linking of glutaminyl residues of a protein/peptide substrate to lysyl residues of a protein/peptide co-substrate. In addition to lysyl residues, other second nucleophilic co-substrates may include monoamines or polyamines (to form mono- or bi-substituted/crosslinked adducts) or −OH groups (to form ester linkages). In absence of co-substrates, the nucleophile may be water, resulting in the net deamidation of the glutaminyl residue. Transglutaminase activity has been suggested to be involved in molecular mechanisms responsible for both physiological or pathological processes. In particular, transglutaminase activity has been shown to be responsible for human autoimmune diseases, and Celiac Disease is just one of them. Interestingly, neurodegenerative diseases, such as Alzheimer’s Disease, Parkinson’s Disease, supranuclear palsy, Huntington’s Disease and other polyglutamine diseases, are characterized in part by aberrant cerebral transglutaminase activity and by increased cross-linked proteins in affected brains. Here we describe the possible molecular mechanisms by which these enzymes could be responsible for such diseases and the possible use of transglutaminase inhibitors for patients with diseases characterized by aberrant transglutaminase activity.

Possible roles of transglutaminase-catalyzed reactions in the pathogenesis of human neurodegenerative diseases.

Abstract: Transglutaminases are Ca 2+ -dependent enzymes which catalyze post-translational modifications of proteins. The main activity of these enzymes is the cross-linking of glutaminyl residues of a protein/peptide substrate to lysyl residues of a protein/peptide co-substrate. In addition to lysyl residues, other second nucleophilic co-substrates may include monoamines or polyamines (to form mono- or bi-substituted /crosslinked adducts) or –OH groups (to form ester linkages). In absence of co-substrates, the nucleophile may be water, resulting in the net deamidation of the glutaminyl residue. Transglutaminase activity has been suggested to be involved in molecular mechanisms responsible for both physiological or pathological processes. In particular, transglutaminase activity has been shown to be responsible for a widespread human autoimmune disease, the Celiac Disease. Interestingly, neurodegenerative diseases, such as Alzheimer’s Disease, Parkinson’s Disease, supranuclear palsy, Huntington’s Disease and other diseases, are characterized in part by aberrant cerebral transglutaminase activity and by increased cross-linked proteins in affected brains. This review focuses on the possible molecular mechanisms responsible for such diseases and on the possible use of transglutaminase inhibitors for patients with diseases characterized by aberrant transglutaminase activity.

Possible roles of transglutaminases in molecular mechanisms responsible for human neurodegenerative diseases

Transglutaminases are a family of Ca²⁺-dependent enzymes which catalyze post-translational modifications of proteins. The main activity of these enzymes is the cross-linking of glutaminyl residues of a protein/peptide substrate to lysyl residues of a protein/peptide co-substrate. In addition to lysyl residues, other second nucleophilic co-substrates may include monoamines or polyamines (to form mono- or bi-substituted/crosslinked adducts) or –OH groups (to form ester linkages). In absence of co-substrates, the nucleophile may be water, resulting in the net deamidation of the glutaminyl residue. Transglutaminase activity has been suggested to be involved in molecular mechanisms responsible for both physiological or pathological processes. In particular, transglutaminase activity has been shown to be responsible for human autoimmune diseases, Celiac Disease is just one of them. Interestingly, neurodegenerative diseases, such as Alzheimer’s Disease, Parkinson’s Disease, supranuclear palsy, Huntington’s Disease and other polyglutamine diseases, are characterized in part by aberrant cerebral transglutaminase activity and by increased cross-linked proteins in affected brains. This review describes the possible molecular mechanisms by which these enzymes could be responsible for such diseases and the possible use of transglutaminase inhibitors for patients with diseases characterized by aberrant transglutaminase activity.

Phosphate ions and glutaminyl cyclases catalyze the cyclization of glutaminyl residues by facilitating synchronized proton transfers

Phosphate ions and glutaminyl cyclase (QC) both catalyze the formation of pyroglutamate (pE, pGlu) from N-terminal glutamine residues of peptides and proteins. Here, we studied the mechanism of glutamine cyclization using kinetic secondary deuterium and solvent isotope effects. The data suggest that proton transfer(s) are rate determining for the spontaneous reaction, and that phosphate and QC are accelerating the reaction by promoting synchronized proton transfers in a concerted mechanism. Thus, non-enzymatic and enzymatic catalysis of pyroglutamate formation exploit a similar mode of transition-state stabilization.

Functional Significance of Point Mutations in Stress Chaperone Mortalin and Their Relevance to Parkinson Disease

Mortalin/mtHsp70/Grp75 (mot-2), a heat shock protein 70 family member, is an essential chaperone, enriched in cancers, and has been shown to possess pro-proliferative and anti-apoptosis functions. An allelic form of mouse mortalin (mot-1) that differs by two amino acids, M618V and G624R, in the C terminus substrate-binding domain has been reported. Furthermore, genome sequencing of mortalin from Parkinson disease patients identified two missense mutants, R126W and P509S. In the present study, we investigated the significance of these mutations in survival, proliferation, and oxidative stress tolerance in human cells. Using mot-1 and mot-2 recombinant proteins and specific antibodies, we performed screening to find their binding proteins and then identified ribosomal protein L-7 (RPL-7) and elongation factor-1 α (EF-1α), which differentially bind to mot-1 and mot-2, respectively. We demonstrate that mot-1, R126W, or P509S mutant (i) lacks mot-2 functions involved in carcinogenesis, such as p53 inactivation and hTERT/hnRNP-K (heterogeneous nuclear ribonucleoprotein K) activation; (ii) causes increased level of endogenous oxidative stress; (iii) results in decreased tolerance of cells to exogenous oxidative stress; and (iv) shows differential binding and impact on the RPL-7 and EF-1α proteins. These factors may mediate the transformation of longevity/pro-proliferative function of mot-2 to the premature aging/anti-proliferative effect of mutants, and hence may have significance in cellular aging, Parkinson disease pathology, and prognosis.

Possible Role of the Transglutaminase Activity in Molecular Mechanisms Responsible for Human Neurodegenerative Diseases

Transglutaminases are Ca2+-dependent enzymes which catalyze post-translational modifications of proteins. The main activity of these enzymes is the cross-linking of glutaminyl residues of a protein/peptide substrate to lysyl residues of a protein/peptide co-substrate. In addition to lysyl residues, other second nucleophilic co-substrates may include monoamines or polyamines (to form mono- or bi-substituted /crosslinked adducts) or –OH groups (to form ester linkages). In absence of co-substrates, the nucleophile may be water, resulting in the net deamidation of the glutaminyl residue. Transglutaminase activity has been suggested to be involved in molecular mechanisms responsible for both physiological or pathological processes. In particular, transglutaminase activity has been shown to be responsible for a widespread human autoimmune disease, the Celiac Disease. Interestingly, neurodegenerative diseases, such as Alzheimer’s Disease, Parkinson’s Disease, supranuclear palsy, Huntington’s Disease and other polyglutamine diseases, are characterized in part by aberrant cerebral transglutaminase activity and by increased cross-linked proteins in affected brains. This review focuses on the possible molecular mechanisms responsible for such diseases and on the possible therapeutic effects of transglutaminase inhibitors for patients with diseases characterized by aberrant transglutaminase activity.

Possible pathophysiological roles of transglutaminase-catalyzed reactions in the pathogenesis of human neurodegenerative diseases

Transglutaminases (TG, E.C. 2.3.2.13) are related and ubiquitous enzymes that catalyze the cross linking of a glutaminyl residue of a protein/peptide substrate to a lysyl residue of a protein/peptide co-substrate. These enzymes are also capable of catalyzing other post-translational reactions important for cell life. The distribution and the physiological roles of human TGs have been widely studied in numerous cell types and tissues and recently their roles in several diseases have begun to be identified. It has been hypothesized that transglutaminase activity is directly involved in the pathogenetic mechanisms responsible for several human diseases. In particular, tissue TG (tTG, TG2), a member of the TG enzyme family, has been recently shown to be involved in the molecular mechanisms responsible for a very widespread human pathology, Celiac Disease (CD), one of the most common food intolerances described in the western population. The main food agent that provokes the strong and diffuse clinical symptoms has been known for several years to be gliadin, a protein present in a very large number of human foods derived from vegetables. Recently, some biochemical and immunological aspects of this very common disease have been clarified, and “tissue” transglutaminase, a multifunctional and ubiquitous enzyme, has been identified as one of the major factors. The aim of this review is to summarize the most recent findings concerning the relationships between the biochemical properties of the transglutaminase activity and the basic molecular mechanisms responsible for some human diseases, with particular reference to neuropsychiatric disorders. Possible molecular links between CD and neuropsychiatric disorders, and the use of transglutaminase inhibitors are also discussed.

Possible physiopathological effects of the transglutaminase activity on the molecular mechanisms responsible for human neurodegenerative diseases.

Transglutaminases are a class of ubiquitous enzymes which catalyze post-translational modifications of proteins. The main activity of these enzymes is the cross-linking of glutaminyl residues of a protein/peptide substrate to lysyl residues of a protein/peptide co-substrate. In addition to lysyl residues, other second nucleophilic co-substrates may include monoamines or polyamines (to form mono- or bi-substituted /crosslinked adducts) or -OH groups (to form ester linkages). In absence of co-substrates, the nucleophile may be water, resulting in the net deamidation of the glutaminyl residue. Transglutaminase activity has been suggested to be involved in molecular mechanisms responsible for both physiological or pathological processes. Recently, transglutaminase activity has been shown to be responsible for a widespread human autoimmune disease, the Celiac Disease. Interestingly, neurodegenerative diseases, such as Alzheimer's disease, Parkinson's disease, supranuclear palsy, Huntington's disease and other polyglutamine diseases, are characterized in part by aberrant cerebral transglutaminase activity and by increased cross-linked proteins in affected brains. This review focuses on the possible molecular mechanisms responsible for such diseases and on the possible therapeutic effects of transglutaminase inhibitors for patients with diseases characterized by aberrant transglutaminase activity.

Possible physiopathological roles of the transglutaminase activity in the etiopathogenesis of human neurodegenerative diseases.

Transglutaminases are ubiquitous enzymes which catalyze post-translational modifications of proteins. The main activity of these enzymes is the cross-linking of glutaminyl residues of a protein/peptide substrate to lysyl residues of a protein/peptide co-substrate. In addition to lysyl residues, other second nucleophilic co-substrates may include monoamines or polyamines (to form mono- or bi-substituted /crosslinked adducts) or -OH groups (to form ester linkages). In the absence of co-substrates, the nucleophile may be water, resulting in the net deamidation of the glutaminyl residue. Transglutaminase activity has been suggested to be involved in molecular mechanisms responsible for both physiological or pathological processes. For example, neurodegenerative diseases, such as Alzheimer's Disease, Parkinson's Disease, supranuclear palsy, Huntington's Disease and other polyglutamine diseases, are characterized in part by aberrant cerebral transglutaminase activity and by increased cross-linked proteins in affected brains. This review focuses on the possible molecular mechanisms responsible for such diseases and on the possible therapeutic effects of transglutaminase inhibitors for patients with diseases characterized by aberrant transglutaminase activity.

Prince Cangrande’s Collagen: Study of Protein Modification on the Mummy of the Lord of Verona, Italy (1291–1329 AD)

The natural mummy of prince Cangrande, Lord of Verona, Italy (1291–1329 AD) was studied. Two samples were taken: rib bone and muscle. These samples were cleaved with trypsin and analysed by liquid chromatographic methods coupled to mass spectrometry (Q-TOF, ion-trap). Special attention was devoted to nonenzymatic protein modification––the deamidation of asparagine and glutamine. A huge amount of collagen was determined in the tissues of the mummy (covering over 80 % of the sequence)––collagen type I was identified in the rib bone and collagen types I and III in the muscle. A high overall percentage of asparaginyl and glutaminyl residues were deamidated (up to 92 %). In agreement with the literature we can suppose that the deamidation of really old samples (at least 100-years-old) is mainly dependent on the burial conditions and/or thermal age and cannot serve as a precise “molecular clock”.

Transglutaminase 2-dependent Deamidation of Glyceraldehyde-3-phosphate Dehydrogenase Promotes Trophoblastic Cell Fusion

Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is a multifunctional protein as well as a classic glycolytic enzyme, and its pleiotropic functions are achieved by various post-translational modifications and the resulting translocations to intracellular compartments. In the present study, GAPDH in the plasma membrane of BeWo choriocarcinoma cells displayed a striking acidic shift in two-dimensional electrophoresis after cell-cell fusion induction by forskolin. This post-translational modification was deamidation of multiple glutaminyl residues, as determined by molecular mass measurement and tandem mass spectrometry of acidic GAPDH isoforms. Transglutaminase (TG) inhibitors prevented this acidic shift and reduced cell fusion. Knockdown of the TG2 gene by short hairpin RNA reproduced these effects of TG inhibitors. Various GAPDH mutants with replacement of different numbers (one to seven) of Gln by Glu were expressed in BeWo cells. These deamidated mutants reversed the suppressive effect of wild-type GAPDH overexpression on cell fusion. Interestingly, the mutants accumulated in the plasma membrane, and this accumulation was increased according to the number of Gln/Glu substitutions. Considering that GAPDH binds F-actin via an electrostatic interaction and that the cytoskeleton is rearranged in trophoblastic cell fusion, TG2-dependent GAPDH deamidation was suggested to participate in actin cytoskeletal remodeling.

Transglutaminase Activity as a Possible Therapeutical Target in Neurodegenerative Diseases

Transglutaminases are ubiquitous enzymes which catalyze post-translational modifications of proteins. The main activity of these enzymes is the cross-linking of glutaminyl residues of a protein/peptide substrate to lysyl residues of a protein/peptide co-substrate. In addition to lysyl residues, other second nucleophilic co-substrates may include monoamines or polyamines (to form mono- or bi-substituted /crosslinked adducts) or -OH groups (to form ester linkages). In absence of co-substrates, the nucleophile may be water, resulting in the net deamidation of the glutaminyl residue. Transglutaminase activity has been suggested to be involved in molecular mechanisms responsible for both physiological or pathological processes. For example, neurodegenerative diseases, such as Alzheimer's Disease, Parkinson's Disease, supranuclear palsy, Huntington's Disease and other polyglutamine diseases, are characterized in part by aberrant cerebral transglutaminase activity and by increased cross-linked proteins in affected brains. This review focuses on the possible molecular mechanisms responsible for such diseases and on the possible therapeutic effects of selective transglutaminase inhibitors for patients with diseases characterized by aberrant transglutaminase activity. The article presents some promising patents on the transglutaminase activity.

Possible Role of the Transglutaminase-Catalyzed Reactions in the Pathogenesis of Neurodegenerative Diseases

Possible Role of the Transglutaminase-Catalyzed Reactions in the Pathogenesis of Neurodegenerative Diseases Transglutaminases are ubiquitous enzymes which catalyze posttranslational modifications of proteins. The main activity of these enzymes is the cross-linking of glutaminyl residues of a protein/ peptide substrate to lysyl residues of a protein/peptide co-substrate. In addition to lysyl residues, other second nucleophilic cosubstrates may include monoamines or polyamines (to form monoor bi-substituted/crosslinked adducts) or –OH groups (to form ester linkages). In absence of co-substrates, the nucleophile may be water, resulting in the net deamidation of the glutaminyl residue. Transglutaminase activity has been suggested to be involved in molecular mechanisms responsible for both physiological and pathological processes. For example, neurodegenerative diseases, such as Alzheimer’s disease, Parkinson’s disease, supranuclear palsy, Huntington’s disease and other polyglutamine diseases, are characterized in part by aberrant cerebral transglutaminase activity and by increased cross-linked proteins in affected brains. This review focuses on the possible molecular mechanisms responsible for such diseases and on the possible therapeutic effects of transglutaminase inhibitors for patients with diseases characterized by aberrant transglutaminase activity.

Transglutaminase Inhibition as a Possible Therapeutical Approach to Protect Cells from Death in Neurodegenerative Diseases

Transglutaminases are ubiquitous enzymes which catalyze post-translational modifications of proteins. The main activity of these enzymes is the cross-linking of glutaminyl residues of a protein/peptide substrate to lysyl residues of a protein/peptide co-substrate. In addition to lysyl residues, other second nucleophilic co-substrates may include monoamines or polyamines (to form mono- or bi-substituted /crosslinked adducts) or -OH groups (to form ester linkages). In absence of co-substrates, the nucleophile may be water, resulting in the net deamidation of the glutaminyl residue. Recently, "tissue" transglutaminase (transglutaminase 2), a member of the transglutaminase family of enzymes, has been shown to be involved in the molecular mechanisms responsible for some human pathologies, including celiac disease, a very widespread human pathology. Transglutaminase activity has also been hypothesized to be involved in the pathogenetic mechanisms responsible for other several human diseases, including neurodegenerative diseases, often associated to celiac disease. Neurodegenerative diseases, such as Alzheimer's Disease, Parkinson's Disease, supranuclear palsy, Huntington's Disease and other polyglutamine diseases, are characterized in part by aberrant cerebral transglutaminase activity and by increased cross-linked proteins in affected brains. This review focuses on the possible therapeutic effects of selective transglutaminase inhibitors for patients with diseases characterized by aberrant transglutaminase activity and on the strategies to design such transglutaminase inhibitors. In addition, the review also examines available patents that relates to cysteamine and derivatives.

Identification of interaction partners of β‐thymosins: application of thymosin β4 labeled by transglutaminase

In this review, we identify potential interaction partners of the β-thymosin family. The proteins of this family are highly conserved peptides in mammals and yet only one intracellular (G-actin) and one cell-surface protein (β subunit of F(1) -F(0) ATP synthase) were identified as interaction partners of thymosin β4. Cross-linking experiments may be a possible approach to discover additional proteins that interact with the β-thymosin family. It has previously been shown that thymosin β4 can be labeled at its glutaminyl residues with various cadaverines using tissue transglutaminase. Here, we illuminate recent results and give an outlook on upcoming work in the field.

Pathophysiological Roles of Transglutaminase - Catalyzed Reactions in the Pathogenesis of Human Diseases

Transglutaminases (TGs, E.C. 2.3.2.13) are related and ubiquitous enzymes which catalyze the cross linking of a glutaminyl residue of a protein/peptide substrate to a lysyl residue of a protein/peptide co-substrate. These enzymes are also capable of catalyzing other reactions which are important for cell life. To date, at least eight different human TGs have been identified. The distribution and the physiological roles of human TGs have been widely studied in numerous cell types and tissues and recently their roles in several diseases have begun to be identified. It has been hypothesized that transglutaminase activity is directly involved in the patho-genetic mechanisms responsible for several human diseases. In particular, TG2, a member of the TG enzyme family, has been shown to be involved in the molecular mechanisms responsible for a very widespread human pathology, Celiac Disease (CD), one of the most common food intolerances described in the western population. The main food agent that provokes the strong and diffuse clinical symptoms has been known for several years to be gliadin, a protein present in a very large number of human foods derived from vegetables. The aim of this review is to summarize the most recent findings concerning the relationships between the biochemical properties of the transglutaminase activity and the basic molecular mechanisms responsible for CD. In addition, we present some clinical associations of CD with other human diseases, with particular reference to neuropsychiatric disorders. Possible molecular links between biochemical activities of transglutaminase enzymes, CD and neuropsychiatric disorders are discussed.

Evidences for a role of protein cross-links in transglutaminase-related disease

Transglutaminases (TGs) are a large family of related and ubiquitous enzymes that catalyze the cross-linking of a glutaminyl residue of a protein/peptide substrate to a lysyl residue of a protein/peptide co-substrate. Considerable and intense progress has been made in the understanding of the chemistry, molecular biology and cell biology of TGs. The knowledge that very different physiological and pathological processes are dependent on the presence of adequate levels of these cross-linking enzymes and on the amount of both free and protein-conjugated polyamines by TG, has generated an incredible amount of original research and review articles. It is clear that TG-mediated reactions are essential for some biological processes, such as blood coagulation, skin barrier formation and extracellular matrix assembly, but may also be involved in pathogenetic mechanisms responsible for several human diseases, such as cancer, AIDS, neurodegenerative disorders, celiac disease, and eye lens opacification. We present here a comprehensive review of recent insights into the pathophysiology of TGs related to their protein cross-linking activity.