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Smerkolj J, Stojan J, Bavec A, Goličnik M. Substrate-dependent inactivation of recombinant paraoxonase 1 during catalytic dihydrocoumarin turnover and the protective properties of surfactants. Chem Biol Interact 2023; 382:110563. [PMID: 37286155 DOI: 10.1016/j.cbi.2023.110563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 05/17/2023] [Accepted: 05/22/2023] [Indexed: 06/09/2023]
Abstract
Human paraoxonase-1 (PON1) is the most studied member of the paraoxonases (PONs) family and catalyzes the hydrolysis of various substrates (lactones, aryl esters, and paraoxon). Numerous studies link PON1 to oxidative stress-related diseases such as cardiovascular disease, diabetes, HIV infection, autism, Parkinson's, and Alzheimer's, where the kinetic behavior of an enzyme is characterized by initial rates or by modern methods that obtain enzyme kinetic parameters by fitting the computed curves over the entire time-courses of product formation (progress curves). In the analysis of progress curves, the behavior of PON1 during hydrolytically catalyzed turnover cycles is unknown. Hence, progress curves for enzyme-catalyzed hydrolysis of the lactone substrate dihydrocoumarin (DHC) by recombinant PON1 (rePON1) were analyzed to investigate the effect of catalytic DHC turnover on the stability of rePON1. Although rePON1 was significantly inactivated during the catalytic DHC turnover, its activity was not lost due to the product inhibition or spontaneous inactivation of rePON1 in the sample buffers. Examination of the progress curves of DHC hydrolysis by rePON1 led to the conclusion that rePON1 inactivates itself during catalytic DHC turnover hydrolysis. Moreover, human serum albumin or surfactants protected rePON1 from inactivation during this catalytic process, which is significant because the activity of PON1 in clinical samples is measured in the presence of albumin.
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Affiliation(s)
- Janez Smerkolj
- Institute of Biochemistry and Molecular Genetics, Faculty of Medicine, University of Ljubljana, Vrazov trg 2, SI 1000, Ljubljana, Slovenia
| | - Jure Stojan
- Institute of Biochemistry and Molecular Genetics, Faculty of Medicine, University of Ljubljana, Vrazov trg 2, SI 1000, Ljubljana, Slovenia
| | - Aljoša Bavec
- Institute of Biochemistry and Molecular Genetics, Faculty of Medicine, University of Ljubljana, Vrazov trg 2, SI 1000, Ljubljana, Slovenia
| | - Marko Goličnik
- Institute of Biochemistry and Molecular Genetics, Faculty of Medicine, University of Ljubljana, Vrazov trg 2, SI 1000, Ljubljana, Slovenia.
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Petrič B, Redenšek Trampuž S, Dolžan V, Gregorič Kramberger M, Trošt M, Maraković N, Goličnik M, Bavec A. Investigation of Paraoxonase-1 Genotype and Enzyme-Kinetic Parameters in the Context of Cognitive Impairment in Parkinson's Disease. Antioxidants (Basel) 2023; 12:antiox12020399. [PMID: 36829958 PMCID: PMC9952446 DOI: 10.3390/antiox12020399] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Revised: 02/01/2023] [Accepted: 02/04/2023] [Indexed: 02/10/2023] Open
Abstract
Cognitive impairment is a common non-motor symptom of Parkinson's disease (PD), which often progresses to PD dementia. PD patients with and without dementia may differ in certain biochemical parameters, which could thus be used as biomarkers for PD dementia. The enzyme paraoxonase 1 (PON1) has previously been investigated as a potential biomarker in the context of other types of dementia. In a cohort of PD patients, we compared a group of 89 patients with cognitive impairment with a group of 118 patients with normal cognition. We determined the kinetic parameters Km and Vmax for PON1 for the reaction with dihydrocoumarin and the genotype of four single nucleotide polymorphisms in PON1. We found that no genotype or kinetic parameter correlated significantly with cognitive impairment in PD patients. However, we observed associations between PON1 rs662 and PON1 Km (p < 10-10), between PON1 rs662 and PON1 Vmax (p = 9.33 × 10-7), and between PON1 rs705379 and PON1 Vmax (p = 2.21 × 10-10). The present study is novel in three main aspects. (1) It is the first study to investigate associations between the PON1 genotype and enzyme kinetics in a large number of subjects. (2) It is the first study to report kinetic parameters of PON1 in a large number of subjects and to use time-concentration progress curves instead of initial velocities to determine Km and Vmax in a clinical context. (3) It is also the first study to calculate enzyme-kinetic parameters in a clinical context with a new algorithm for data point removal from progress curves, dubbed iFIT. Although our results suggest that in the context of PD, there is no clinically useful correlation between cognitive status on the one hand and PON1 genetic and enzyme-kinetic parameters on the other hand, this should not discourage future investigation into PON1's potential associations with other types of dementia.
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Affiliation(s)
- Boštjan Petrič
- Institute of Biochemistry and Molecular Genetics, Faculty of Medicine, University of Ljubljana, 1000 Ljubljana, Slovenia
| | - Sara Redenšek Trampuž
- Institute of Biochemistry and Molecular Genetics, Faculty of Medicine, University of Ljubljana, 1000 Ljubljana, Slovenia
| | - Vita Dolžan
- Institute of Biochemistry and Molecular Genetics, Faculty of Medicine, University of Ljubljana, 1000 Ljubljana, Slovenia
| | - Milica Gregorič Kramberger
- Department of Neurology, University Medical Center, 1000 Ljubljana, Slovenia
- Chair of Neurology, Faculty of Medicine, University of Ljubljana, 1000 Ljubljana, Slovenia
- Karolinska Institutet, Department of Neurobiology, Care Sciences and Society (NVS), Division of Clinical Geriatrics, 141 83 Huddinge, Sweden
| | - Maja Trošt
- Department of Neurology, University Medical Center, 1000 Ljubljana, Slovenia
- Chair of Neurology, Faculty of Medicine, University of Ljubljana, 1000 Ljubljana, Slovenia
| | - Nikola Maraković
- Institute of Biochemistry and Molecular Genetics, Faculty of Medicine, University of Ljubljana, 1000 Ljubljana, Slovenia
- Institute for Medical Research and Occupational Health, 10000 Zagreb, Croatia
| | - Marko Goličnik
- Institute of Biochemistry and Molecular Genetics, Faculty of Medicine, University of Ljubljana, 1000 Ljubljana, Slovenia
| | - Aljoša Bavec
- Institute of Biochemistry and Molecular Genetics, Faculty of Medicine, University of Ljubljana, 1000 Ljubljana, Slovenia
- Correspondence:
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Petrič B, Goličnik M, Bavec A. iFIT: An automated web tool for determining enzyme-kinetic parameters based on the high-curvature region of progress curves. Acta Chim Slov 2022; 69:478-482. [PMID: 35861063 DOI: 10.17344/acsi.2022.7359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 02/16/2022] [Accepted: 03/21/2022] [Indexed: 11/19/2022] Open
Abstract
The area where progress curve exhibits maximum curvature contains the most information about kinetic parameters. To determine these parameters more accurately from progress curves, we propose an iterative approach that calculates the area of maximum curvature based on an estimate of kinetic parameters and then recalculates the parameters based on time-concentration data points within this area. Based on this algorithm, we developed a computer script called iFIT as a free web application at http://www.i-fit.si. The benefits of working with iFIT are that it decreases the importance of initial substrate concentration and the impact of certain side reactions on the final calculated kinetic parameters.
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Affiliation(s)
- Boštjan Petrič
- University of Ljubljana, Faculty of Medicine, Institute of Biochemistry and Molecular Genetics, Vrazov trg2, Ljubljana.
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Taler-Verčič A, Goličnik M, Bavec A. The Structure and Function of Paraoxonase-1 and Its Comparison to Paraoxonase-2 and -3. Molecules 2020; 25:molecules25245980. [PMID: 33348669 PMCID: PMC7766523 DOI: 10.3390/molecules25245980] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 12/04/2020] [Accepted: 12/15/2020] [Indexed: 12/12/2022] Open
Abstract
Serum paraoxonase-1 (PON1) is the most studied member of the group of paraoxonases (PONs). This enzyme possesses three enzymatic activities: lactonase, arylesterase, and paraoxonase activity. PON1 and its isoforms play an important role in drug metabolism as well as in the prevention of cardiovascular and neurodegenerative diseases. Although all three members of the PON family have the same origin and very similar amino acid sequences, they have different functions and are found in different locations. PONs exhibit substrate promiscuity, and their true physiological substrates are still not known. However, possible substrates include homocysteine thiolactone, an analogue of natural quorum-sensing molecules, and the recently discovered derivatives of arachidonic acid—bioactive δ-lactones. Directed evolution, site-directed mutagenesis, and kinetic studies provide comprehensive insights into the active site and catalytic mechanism of PON1. However, there is still a whole world of mystery waiting to be discovered, which would elucidate the substrate promiscuity of a group of enzymes that are so similar in their evolution and sequence yet so distinct in their function.
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Abstract
Paraoxonase 1 (PON1) enzyme has antioxidative properties and is present in mammalian blood and several other body fluids. In blood, PON1 is usually integrated into the high-density lipoprotein (HDL) cholesterol. PON1 is a highly versatile enzyme displaying diverse functions such as arylesterase, lactonase, and paraoxonase, among others. PON1 activities are usually investigated with artificial substrates, for example, dihydrocoumarin and thiobutyl butyrolactone for lactonase activity. The PON1 enzyme activities measured with different substrates tend to be falsely assumed as being equivalent in the literature, although there are poor or weak correlations among the PON1 enzyme activities with different substrates. In addition, and despite our knowledge of the factors influencing PON1 paraoxonase and arylesterase activities, there is little knowledge of PON1 lactonase activity variations and attendant mechanisms. This is important considering further that the lactonase activity is the native activity of PON1. We report here a multi-omics analysis of PON1 lactonase activity. The influence of genetic variations, particularly of single nucleotide polymorphisms and epigenetic, proteomic, and lipidomic variations on PON1 lactonase activity are reviewed. In addition, the influence of various environmental, clinical, and demographic variables on PON1 lactonase activity is discussed. Finally, we examine the associations between PON1 lactonase activity and health states and common complex diseases such as atherosclerosis, dementias, obesity, and diabetes. To the best of our knowledge, this is the first multi-omics analysis of PON1 lactonase activity with an eye to future applications in basic life sciences and translational medicine and the nuances of critically interpreting PON1 function with lactones as substrates.
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Affiliation(s)
- Boštjan Petrič
- Institute of Biochemistry and Molecular Genetics, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Tanja Kunej
- University of Ljubljana, Biotechnical Faculty, Department of Animal Science, Domžale, Slovenia
| | - Aljoša Bavec
- Institute of Biochemistry and Molecular Genetics, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
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Abstract
Although paraoxonase-1 (PON1) activity has been demonstrated to be a reliable biomarker of various diseases, clinical studies have been based only on relative comparison of specific enzyme activities, which capture differences mainly due to (usually unknown) PON1 concentration. Hence, the aim of this report is to present for the first time the simple evaluation method for determining autonomous kinetic parameter of PON1 that could be also associated with polymorphic forms and diseases; i.e. the Michaelis constant which is enzyme concentration independent quantity. This alternative approach significantly reduces the number of experiments needed, and it yields the results with great accuracy.
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Affiliation(s)
- Marko Goličnik
- Institute of Biochemistry, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Aljoša Bavec
- Institute of Biochemistry, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
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Bosak A, Bavec A, Konte T, Šinko G, Kovarik Z, Goličnik M. Interactions of Paraoxonase-1 with Pharmacologically Relevant Carbamates. Molecules 2020; 25:E211. [PMID: 31947900 PMCID: PMC6983073 DOI: 10.3390/molecules25010211] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 12/30/2019] [Accepted: 01/02/2020] [Indexed: 12/12/2022] Open
Abstract
Mammalian paraoxonase-1 hydrolyses a very broad spectrum of esters such as certain drugs and xenobiotics. The aim of this study was to determine whether carbamates influence the activity of recombinant PON1 (rePON1). Carbamates were selected having a variety of applications: bambuterol and physostigmine are drugs, carbofuran is used as a pesticide, while Ro 02-0683 is diagnostic reagent. All the selected carbamates reduced the arylesterase activity of rePON1 towards the substrate S-phenyl thioacetate (PTA). Inhibition dissociation constants (Ki), evaluated by both discontinuous and continuous inhibition measurements (progress curves), were similar and in the mM range. The rePON1 displayed almost the same values of Ki constants for Ro 02-0683 and physostigmine while, for carbofuran and bambuterol, the values were approximately ten times lower and two times higher, respectively. The affinity of rePON1 towards the tested carbamates was about 3-40 times lower than that of PTA. Molecular modelling of rePON1-carbamate complexes suggested non-covalent interactions with residues of the rePON1 active site that could lead to competitive inhibition of its arylesterase activity. In conclusion, carbamates can reduce the level of PON1 activity, which should be kept in mind, especially in medical conditions characterized by reduced PON1 levels.
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Affiliation(s)
- Anita Bosak
- Institute for Medical Research and Occupational Health, HR 10000 Zagreb, Croatia (Z.K.)
| | - Aljoša Bavec
- Institute of Biochemistry, Faculty of Medicine, University of Ljubljana, SI 1000 Ljubljana, Slovenia; (A.B.); (T.K.)
| | - Tilen Konte
- Institute of Biochemistry, Faculty of Medicine, University of Ljubljana, SI 1000 Ljubljana, Slovenia; (A.B.); (T.K.)
| | - Goran Šinko
- Institute for Medical Research and Occupational Health, HR 10000 Zagreb, Croatia (Z.K.)
| | - Zrinka Kovarik
- Institute for Medical Research and Occupational Health, HR 10000 Zagreb, Croatia (Z.K.)
| | - Marko Goličnik
- Institute of Biochemistry, Faculty of Medicine, University of Ljubljana, SI 1000 Ljubljana, Slovenia; (A.B.); (T.K.)
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Bavec A, Knez D, Makovec T, Stojan J, Gobec S, Goličnik M. Exploring the aryl esterase catalysis of paraoxonase-1 through solvent kinetic isotope effects and phosphonate-based isosteric analogues of the tetrahedral reaction intermediate. Biochimie 2014; 106:184-6. [DOI: 10.1016/j.biochi.2014.08.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Accepted: 08/21/2014] [Indexed: 01/24/2023]
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Bavec A. (Poly)peptide-based therapy for diabetes mellitus: insulins versus incretins. Life Sci 2014; 99:7-13. [PMID: 24412390 DOI: 10.1016/j.lfs.2013.12.210] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Revised: 12/22/2013] [Accepted: 12/26/2013] [Indexed: 12/25/2022]
Abstract
Insulin therapy remains the standard of care for achieving and maintaining adequate glycemic control, especially in hospitalized patients with critical and noncritical illnesses. Insulin therapy is more effective against elevated fasting glycaemia but less in the reduction of postprandial hyperglycaemia. It is associated with a high incidence of hypoglycemia and weight gain. Contrary, GLP-1 mimetic therapy improves postprandial glycaemia without the hypoglycaemia and weight gain associated with aggressive insulin therapy. Moreover, it has the potential to reduce cardiovascular related morbidity. However, its increased immunogenicity and severe gastrointestinal adverse effects present a huge burden on patients. Thus, a right combination of basal insulin which has lowering effect on fasting plasma glucose and GLP-1 mimetic with its lowering effect on postprandial plasma glucose with minimal gastrointestinal adverse effects, seems the right therapy choice from a clinical point of view for some diabetic patients. In this article, we discuss the pros and cons of the use of insulin analogues and GLP-1 mimetics that are associated with the treatment of type 2 diabetes.
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Affiliation(s)
- Aljoša Bavec
- Institute of Biochemistry, Faculty of Medicine, University of Ljubljana, Vrazov trg 2, 1000 Ljubljana, Slovenia.
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Deželak M, Bavec A. Glucagon like-peptide-1 receptor is covalently modified by endogenous mono-ADP-ribosyltransferase. Mol Biol Rep 2011; 39:4375-81. [DOI: 10.1007/s11033-011-1225-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2010] [Accepted: 06/20/2011] [Indexed: 10/17/2022]
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Bavec A. Structure, Function and Regulation of Group IV Phospholipase A2 Family. Acta Chim Slov 2011; 58:195-202. [PMID: 24062027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023] Open
Abstract
The Group IV phospholipase A2 family is consisted of six intracellular enzymes. They catalyze hydrolysis of the sn-2 ester bond of glycerophospholipids, releasing fatty acid metabolites and lysophospholipids. Agonist-induced release of arachidonic acid for the production of eicosanoids by PLA2IValpha enzyme is important in regulating normal and pathological processes in a variety of target tissues. Here, we compare PLA2IValpha, and its paralogs β, γ, δ, ε and ζ in term of of their structure, function and regulation.
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Deželak M, Bavec A. Third intracellular loop of glucagon like-peptide-1 receptor is coupled with endogenous mono-ADP-ribosyltransferase - novel type of receptor regulation? Eur J Pharmacol 2011; 666:35-42. [PMID: 21635883 DOI: 10.1016/j.ejphar.2011.05.033] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2011] [Revised: 05/13/2011] [Accepted: 05/17/2011] [Indexed: 10/18/2022]
Abstract
Our previous studies revealed the main role of the third intracellular loop (IC(3)) of glucagon-like peptide-1 receptor (GLP-1 receptor), in G-protein activation, where the presence or absence of agonist and the receptor phosphorylation seemed to be the only regulatory mechanisms. In order to further study the signaling mechanisms of GLP-1 receptor, we investigated the effect of the third intracellular loop-derived peptide on endogenous mono-ADP-ribosyltransferase mediated mono-ADP-ribosylation of G-proteins β subunit in CHO cells. Results showed an inhibitory effect of IC(3) peptide on mono-ADP-ribosylation of β subunit, obviously via the mechanism of competitive inhibition. Excluding the activity of this inhibitory mechanism via pertussis toxin-sensitive G proteins, the direct functional coupling of IC(3) of GLP-1 receptor and endogenous mono-ADP-ribosyltransferase was confirmed. We suggest that this arginine specific enzymatic posttranslational modification of third intracellular loop of GLP-1 receptor might represent a possible novel mechanism of receptor activity regulation and the pharmacological potential in treatment of diabetes mellitus type 2.
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Affiliation(s)
- Matjaž Deželak
- Institute of Biochemistry, Faculty of Medicine, University of Ljubljana, Vrazov trg 2, 1000 Ljubljana, Slovenia
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Stempelj M, Bavec A, Ferjan I. Regulation of nerve growth factor induced histamine and arachidonic acid release from rat mast cells by cannabinoids. Inflamm Res 2006; 55 Suppl 1:S09-10. [PMID: 16705373 DOI: 10.1007/s00011-005-0017-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Affiliation(s)
- M Stempelj
- Department of Pharmacology and Experimental Toxicology, Faculty of Medicine, University of Ljubljana, Korytkova 2, 1000, Ljubljana, Slovenia,
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Bavec A, Slajpah M, Lenasi H, Yorko M, Breskvar K. G-protein coupled progesterone receptors in the plasma membrane of fungus Rhizopus nigricans. Pflugers Arch 2001; 440:R179-80. [PMID: 11005662] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
We have demonstrated simultaneous existence of progesterone receptors and GTPase activity in the membranes prepared from the filamentous fungus Rhizopus nigricans. The results obtained with pertussis toxin treated fungal mycelium suggest that these receptors do not couple to Gi-Go-proteins and play a role in the induction of steroid hydroxylating enzyme system by steroid substrates in the fungus.
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Affiliation(s)
- A Bavec
- Institute of Biochemistry, Medical Faculty, University of Ljubljana, Slovenia
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Bavec A, Šlajpah M, Lenasi H, Zorko M, Breskvar K. G-Protein coupled progesterone receptors in the plasma membrane of fungus Rhizopus nigricans. Pflugers Arch 2000; 440:R179-R180. [DOI: 10.1007/s004240000055] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Abstract
Peptitergent PD1 shows complex effects on GTPase activity of rat brain cortical membranes: inhibition in the presence of lower concentrations of GTP and activation at a higher concentration, above 0.5 microM, of GTP. Its effect is dose dependent and is characterized by an EC50 of 1.8 +/- 0.2 microM and a Hill coefficient of 1.6 +/- 0.3, and it increases both Km and Vmax of the GTP hydrolysis. PD1 that was unable to solubilize G-proteins from the membranes probably acts on them by direct binding near the C-terminal alpha-helical region of the Galpha subunit, similarly to mastoparan.
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Affiliation(s)
- A Bavec
- Institute of Biochemistry, Medical Faculty, University of Ljubljana, Slovenia
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