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Gaddi GM, Caro-Ramírez JY, Parente JE, Williams PAM, Ferrer EG. Copper-flavonoid family of complexes involved in alkaline phosphatase activation. Biometals 2023; 36:1221-1239. [PMID: 37258944 DOI: 10.1007/s10534-023-00511-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Accepted: 05/13/2023] [Indexed: 06/02/2023]
Abstract
The flavonoid naringenin and a family of naringenin derivative Cu(II) complexes having phenanthroline-based second ligands were selected to study alkaline phosphatase activation. This enzyme plays a critical role in tissue formation, increasing the inorganic phosphate formation, favoring mineralization, and being essential to producing bone mineralization. The effects of those compounds on the function and structure of the enzyme were evaluated by kinetic measurements, fluorescence, FTIR, and UV-Vis spectroscopies. The results showed that naringenin did not affect alkaline phosphatase activity, having a value of the Michaelis-Menten-constant close to the enzyme (Km = 3.07 × 10-6). The binary complex, Cu(II)-naringenin, and the ternary complex Cu(II)-naringenin-phenanthroline behaved as an enzyme activator in all the concentrations range used in this study. Those complexes increased in c.a. 1.9% the catalytic efficiency concerning enzyme and naringenin. The ternary complex Cu(II)-naringenin-bathophenanthroline, provokes an activator mixed effect, dependent on the substrate concentrations. The different kinetic behavior can be correlated with different conformational changes observed under the interaction with ALP. Fluorescence experiments showed a raising of the binding constant with temperature. FTIR determinations showed that the complex with bathophenanthroline modifies the ALP structure but maintains the helical structure. The other copper complexes provoked a structural unfolding, decreasing the α-helix content. None of them affect the dephosphorylation enzyme ability. Even though the interactions and structural modifications on ALP are different, it is evident that the presence of copper favors enzymatic activity. The observed electrostatic interactions probably benefit the dissociation of the bound phosphate. The results suggest potential biological applications for the studied compounds.
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Affiliation(s)
- Gisela M Gaddi
- CEQUINOR, CONICET-UNLP-Asoc. CICPBA, Faculty of Exact Sciences, National University of La Plata, Bv. 120 No 1465, 1900, La Plata, Argentina
| | - Janetsi Y Caro-Ramírez
- CEQUINOR, CONICET-UNLP-Asoc. CICPBA, Faculty of Exact Sciences, National University of La Plata, Bv. 120 No 1465, 1900, La Plata, Argentina
| | - Juliana E Parente
- CEQUINOR, CONICET-UNLP-Asoc. CICPBA, Faculty of Exact Sciences, National University of La Plata, Bv. 120 No 1465, 1900, La Plata, Argentina
| | - Patricia A M Williams
- CEQUINOR, CONICET-UNLP-Asoc. CICPBA, Faculty of Exact Sciences, National University of La Plata, Bv. 120 No 1465, 1900, La Plata, Argentina
| | - Evelina G Ferrer
- CEQUINOR, CONICET-UNLP-Asoc. CICPBA, Faculty of Exact Sciences, National University of La Plata, Bv. 120 No 1465, 1900, La Plata, Argentina.
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Assessment of Seasonal and Diurnal Variations of Alkaline Phosphatase Activity in Pasteurized Milk. APPLIED SCIENCES-BASEL 2022. [DOI: 10.3390/app12104833] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The present study was conducted to detect the concentration levels of ALP (alkaline phosphatase) in pasteurized milk and determine whether the pasteurization was successful or not, according to WHO Directives, which clearly state that the ALP (alkaline phosphatase) substance in pasteurized milk must be totally inactivated, by implementing a newly developed method. The study, additionally, focused on repeatability, stability of results, the effect of the environmental temperature, the effect of the different origins of the milk and convenience with respect to performance characteristics of three methods for the detection of ALP. The milk samples were collected from different areas of Greece during February 2016–February 2018 and May 2019–January 2020. The novel enzymatic biochemical method, named the “AP test”, showed superior characteristics for a diversity of materials such as milk, whey, cheese and butter in comparison to the other two methods that were used for screening and quantitative estimation of the concentration of ALP in samples.
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Study of alkaline phosphatase interaction with putrescine using multi-spectroscopic and docking methods. Colloids Surf B Biointerfaces 2020; 185:110509. [DOI: 10.1016/j.colsurfb.2019.110509] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Revised: 09/13/2019] [Accepted: 09/14/2019] [Indexed: 12/19/2022]
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Sharifian S, Homaei A, Kim SK, Satari M. Production of newfound alkaline phosphatases from marine organisms with potential functions and industrial applications. Process Biochem 2018. [DOI: 10.1016/j.procbio.2017.10.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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Wu M, Wang J, Wang Z, Zhao J, Hu Y, Chen X. Sequence and functional analysis of intestinal alkaline phosphatase from Lateolabrax maculatus. FISH PHYSIOLOGY AND BIOCHEMISTRY 2017; 43:1463-1476. [PMID: 28551866 DOI: 10.1007/s10695-017-0385-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Accepted: 05/11/2017] [Indexed: 06/07/2023]
Abstract
Alkaline phosphatases (Alps) belong to a class of phosphate transferases that dephosphorylate lipopolysaccharide (LPS), adenosine triphosphate, and nucleotides. In this study, a 1874-base pair (bp) intestinal alp cDNA sequence was cloned from Lateolabrax maculatus and designated as Lm-alpi. It contained a 1611 bp open reading frame which encoded a protein with 537 amino acids. Protein sequence alignment showed that Lm-AlpI shared 29.8-79.8% identity with its homologs. Lm-AlpI catalytic sites contained three metal ion sites (two Zn2+ and one Mg2+), referring to D73, H184, D348, H349, H352, H464, D389, and H390 residues, which are essential for enzymatic activity and conservation in different organisms. Two predicted disulfide bonds in Lm-AlpI were composed of four cysteines (C152-C214 and C499-C506), which were homologous to those of mammals. Immunohistochemical staining revealed that Lm-AlpI was mainly expressed on the mucosal surface of the gastrointestinal tract, including stomach, intestine, and gastric cecum. Lm-AlpI was mainly located on the plasma membrane of transiently transfected HeLa cells. The mRNA of Lm-alpi was mainly expressed in the intestine, and its expression levels gradually increased after LPS treatment and further increased by 1.81-fold after 48 h. After desalting culture, the relative mRNA expression level of Lm-alpi decreased at 30 and 50 days after hatching (DAH) and then returned to normal levels at 70 DAH. Further experiments demonstrated that the enzyme activity of Lm-AlpI exhibited an expression pattern similar to that of the mRNA expression of Lm-alpi after LPS treatment and desalting culture. This study provided valuable information on the Lm-AlpI functions associated with the mucosal immunity and salinity adaptation of L. maculatus.
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Affiliation(s)
- Minglin Wu
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai, 201306, China
- Fisheries Research Institute, Anhui Academy of Agricultural Sciences, NO.40 South Nongke Road, Luyang District, Hefei, Anhui, 230000, China
| | - Jiaqi Wang
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai, 201306, China
| | - Zhipeng Wang
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai, 201306, China
| | - Jinliang Zhao
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai, 201306, China
| | - Yuting Hu
- Fisheries Research Institute, Anhui Academy of Agricultural Sciences, NO.40 South Nongke Road, Luyang District, Hefei, Anhui, 230000, China
| | - Xiaowu Chen
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai, 201306, China.
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Sharma U, Pal D, Singh SK, Kakkar N, Prasad R. Reduced L/B/K alkaline phosphatase gene expression in renal cell carcinoma: plausible role in tumorigenesis. Biochimie 2014; 104:27-35. [PMID: 24909115 DOI: 10.1016/j.biochi.2014.05.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Accepted: 05/28/2014] [Indexed: 01/18/2023]
Abstract
Renal cell carcinoma (RCC) is the most common kidney cancer in adults. Although several genes have been found to be involved in carcinogenesis of RCC, more great efforts are needed to identify new genes which are responsible for the process. Clear cell RCC, originates from proximal tubule cells, is the most common pathological type of RCC. Alkaline phosphatase (ALP) is a marker enzyme of brush border membrane of proximal tubular cells. Our previous studies showed a significant decreased activity of Liver/Bone/Kidney (L/B/K) alkaline phosphatase in RCC. In the present study, we explored the molecular basis of the decreased activity of ALP in RCC. Immunohistochemistry, immunofluorescence and flow cytometry analysis showed decreased ALP protein in RCC. Additionally, real time PCR documented significantly reduced ALP gene expression (P = 0.009). Moreover, RCC cell lines (ACHN and A498) transfected with full length L/B/K cDNA showed decreased migratory property as well as viability of these cells as compared with controls (P = 0.000). Further, L/B/K ALP cDNA transfected cells (ACHN and A498) showed significant increased apoptosis as compared to control (P = 0.000). These findings suggest the new role of ALP in cell viability and apoptosis and involvement in RCC tumorigenesis. However, further studies are needed to explore the exact molecular mechanism.
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Affiliation(s)
| | - Deeksha Pal
- Department of Biochemistry, PGIMER, Chandigarh, India
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Stabilization of Bovine Intestine Alkaline Phosphatase by Sugars. Biosci Biotechnol Biochem 2014; 76:95-100. [DOI: 10.1271/bbb.110553] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Palaniappan PRM, Vijayasundaram V, Prabu SM. A study of the subchronic effects of arsenic exposure on the liver tissues of Labeo rohita using Fourier transform infrared technique. ENVIRONMENTAL TOXICOLOGY 2011; 26:338-344. [PMID: 20014409 DOI: 10.1002/tox.20557] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2009] [Revised: 10/25/2009] [Accepted: 10/29/2009] [Indexed: 05/28/2023]
Abstract
In this work, an attempt has been made to study the subchronic effects of arsenic exposure on the biochemical composition; mainly proteins of the liver tissues of Labeo rohita fingerlings by using Fourier transform infrared (FT-IR) spectroscopic technique. The study was carried out using a Perkin Elmer-Spectrum Rx1 spectrometer. Because of arsenic exposure, significant reductions in the intensity as well as area of amide bands have been observed in the liver tissues. The decreased intensity of the amide bands could be interpreted as the result of alteration of the protein synthesis due to the high affinity of metal compounds towards different amino acid residues of proteins. Further, meso-2, 3-dimercaptosuccinic acid (DMSA) treatment shows the recovery of the protein content in the liver tissues. To confirm that the changes observed are only due to the bio-accumulation of arsenic, the concentration of arsenic in the liver tissues of Labeo rohita was determined by using Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES). It is observed that the arsenic level in the control tissues is found to be below detectable limit, whereas the arsenic exposed liver shows an accumulation of 66.68 ± 0.43 μg/g and DMSA treatment reduces the arsenic content to 17.96 ± 0.19 μg/g. In conclusion, this study gives clear evidence that the use of FT-IR spectroscopy is a powerful approach to achieve more insight into the protein alterations caused by arsenic.
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Affiliation(s)
- Pl R M Palaniappan
- Department of Physics, Annamalai University, Annamalai Nagar 608 002, India.
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Ferraris S, Spriano S, Bianchi CL, Cassinelli C, Vernè E. Surface modification of Ti-6Al-4 V alloy for biomineralization and specific biological response: part II, alkaline phosphatase grafting. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2011; 22:1835-1842. [PMID: 21660585 DOI: 10.1007/s10856-011-4365-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2011] [Accepted: 05/28/2011] [Indexed: 05/30/2023]
Abstract
Titanium and its alloys are the most widespread materials for the realization of orthopaedic and dental implants due to their good mechanical properties and biocompatibility. Surface functionalization of biomaterials aimed to improve and quicken implant integration and tissue regeneration is an active research field. The opportunity to confer biological activity (ability to directly stimulate cells with proper biological signals) to the Ti6Al4 V alloy, previously modified to be bioactive from the inorganic point of view (apatite precipitation), was explored in this research work. The alkaline phosphatase (ALP) enzyme was grafted to metal surface via tresyl chloride activation, maintaining its activity. A synergistic effect between biological functionalization and inorganic bioactivity was observed.
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Affiliation(s)
- S Ferraris
- DISMIC Department, Politecnico di Torino, C.so Duca degli Abruzzi, 24, 10129, Turin, Italy.
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Palaniappan PR, Pramod KS. The effect of titanium dioxide on the biochemical constituents of the brain of Zebrafish (Danio rerio): an FT-IR study. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2011; 79:206-12. [PMID: 21420897 DOI: 10.1016/j.saa.2011.02.038] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2010] [Revised: 02/02/2011] [Accepted: 02/16/2011] [Indexed: 05/25/2023]
Abstract
During recent years, the use of nanoparticles (NPs) in commercial products and industrial applications has increased greatly. One of the most widely used nanoparticles is titanium dioxide (nTiO(2)). It is a very versatile compound that has many uses, depending on its particle size. In the present paper an attempt is made to study the effect of TiO(2) nanoparticles and its bulk material on the biochemical constituents of the brain of Zebrafish (Danio rerio) by using FT-IR technique. FT-IR spectra reveals significant differences in absorbance intensities between the control and TiO(2) exposed brain tissues, reflecting alterations on the major biochemical constituents such as proteins, lipids and nucleic acids in the brain tissues of D. rerio due to TiO(2) exposure. The results further reveal that TiO(2) nanoparticles are more toxic than their bulk counterparts. The higher ratio of integrated area of carbonyl-to-CH(2) peaks (1743 cm(-1):1458 cm(-1)) observed in the present study in the nTiO(2) exposed brain tissues suggests that lipids are being oxidized. Since oxidation can cause an increase in carbonyls and a degradation of lipids, both of these changes could be contributed to the elevated ratio. Further, the observed decreasing ratio of integrated areas of both 1458 cm(-1):1542 cm(-1) and 1743 cm(-1):1542 cm(-1) in the TiO(2) exposed tissues suggests that lipid degradation predominates over carbonyl formation. The observed changes in the biochemical constituents in the brain tissues of D. rerio could be due to the overproduction of ROS.
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Affiliation(s)
- Pl Rm Palaniappan
- Department of Physics, Annamalai University, Annamalai Nagar, India.
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Rankin S, Christiansen A, Lee W, Banavara D, Lopez-Hernandez A. Invited review: The application of alkaline phosphatase assays for the validation of milk product pasteurization. J Dairy Sci 2010; 93:5538-51. [DOI: 10.3168/jds.2010-3400] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2010] [Accepted: 09/03/2010] [Indexed: 11/19/2022]
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Verné E, Ferraris S, Vitale-Brovarone C, Spriano S, Bianchi CL, Naldoni A, Morra M, Cassinelli C. Alkaline phosphatase grafting on bioactive glasses and glass ceramics. Acta Biomater 2010; 6:229-40. [PMID: 19540371 DOI: 10.1016/j.actbio.2009.06.025] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2009] [Revised: 06/03/2009] [Accepted: 06/04/2009] [Indexed: 10/20/2022]
Abstract
Bone integration of orthopaedic or dental implants and regeneration of damaged bone at the surgical site are still unresolved problems in prosthetic surgery. For this reason, biomimetic surfaces (i.e. both inorganic and biological bioactive surfaces) represent a challenge for bone implantation. In this research work a hydrolase enzyme (alkaline phosphatase) was covalently grafted to inorganic bioactive glass and glass ceramic surfaces, in order to impart biological bioactivity. The functionalized samples were analysed by means of X-ray photoelectron spectroscopy in order to verify enzyme presence on the surface. Enzyme activity was measured by means of UV-visual spectroscopy after reaction with the natural substrate. Scanning electron microscopy-energy-dispersive spectroscopy observations allowed monitoring of the morphological and chemical modification of the materials during the different steps of functionalization. In vitro inorganic bioactivity was investigated by soaking samples in simulated body fluid. Enzymatic activity of the samples was tested and compared before and after soaking. Enzymatic activity of the solution was monitored at different experimental times. This study demonstrates that alkaline phosphatase could be successfully grafted onto different bioactive surfaces while maintaining its activity. Presence of the enzyme in vitro enhances the inorganic bioactivity of the materials tested.
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Palaniappan PL, Vijayasundaram V. The effect of arsenic exposure and the efficacy of DMSA on the proteins and lipids of the gill tissues of Labeo rohita. Food Chem Toxicol 2009; 47:1752-9. [DOI: 10.1016/j.fct.2009.04.016] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2009] [Revised: 03/13/2009] [Accepted: 04/15/2009] [Indexed: 10/20/2022]
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Toyran N, Zorlu F, Severcan F. Effect of stereotactic radiosurgery on lipids and proteins of normal and hypoperfused rat brain homogenates: A Fourier transform infrared spectroscopy study. Int J Radiat Biol 2009; 81:911-8. [PMID: 16524846 DOI: 10.1080/09553000600571022] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
PURPOSE The effect of stereotactic radiosurgery on lipids and proteins of normal and hypoperfused rat brain was investigated to see if hypoxic areas are really more resistant to radiation effects or not. MATERIALS AND METHODS Rat brain samples from control, stereotactically irradiated and chronically hypoperfused plus stereotactically irradiated groups were homogenized separately with saline phosphate buffer, and centrifuged at 125,000 g for 15 min. Membrane rich parts (pellet) of these homogenates were used for Fourier Transform Infrared (FTIR) spectroscopy studies. Mann-Whitney U tests were performed on the groups, two by two, to test the significance of the differences between the control group and stereotactically irradiated group as well as the control group and chronically hypoperfused plus stereotactically irradiated group. RESULTS After a single high dose of X-rays to healthy rat brain, the lipid concentration increased slightly, protein content decreased significantly (p < 0.05) and protein-to-lipid ratio decreased slightly. The secondary structure of the proteins was altered in the irradiated brain samples such that the content of a-helical structure decreased significantly (p < 0.01) and random coil increased dramatically (p < 0.05). The effect of radiation on the content of a-helical structure was not found to be significant in the hypoperfused group, but the decrease in the content of random coil was significant (p < 0.01). CONCLUSION Stereotactic radiosurgery of the brain increased the lipid concentration, decreased the protein concentration and consequently resulted in a decrease in the protein to lipid ratio compared to un-irradiated brain. Radiation also altered the secondary structure of protein. The variations in lipid and protein content and the resulting lipid to protein ratio imply that chronically hypoperfused brain is more vulnerable to radiation than non-hypoperfused brain and suggests chronic hypoperfusion does not prevent cerebral damage caused by irradiation. However, irradiation of hypoperfused brain resulted in less alteration in protein structure than in non-hyperfused brain, suggesting higher resistance to irradiation using this endpoint.
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Affiliation(s)
- Neslihan Toyran
- Department of Radiation Oncology, Faculty of Medicine, Hacettepe University, Sihhiye, Ankara, Turkey
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Khodagholi F, Yazdanparast R, Sadeghirizi A. The Glycophosphatidylinositol Anchor Oppositely Affects Unfolding and Refolding of Alkaline Phosphatase. J Biomol Struct Dyn 2007; 25:189-94. [PMID: 17718598 DOI: 10.1080/07391102.2007.10507168] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Regarding the world wide success of artificial chaperone-assisted protein refolding technique and based on its well worked-out mechanism, it is anticipated that the lipid moieties of glycosylphosphatidylinositol (GPI) group, which is present in some membrane proteins, might interfere with the capturing step of the technique. To find an answer, we evaluated the chemical denaturation and also the refolding behavior of insoluble and soluble alkaline phosohatase (ALP), with or without GPI group, respectively. The results indicated that the presence of GPI in the enzyme increased the stability of the protein against chemical denaturation while it decreased its refolding yield by the artificial chaperone refolding technique. The lower refolding yield, compared to soluble ALP (sALP), might be due to a less efficient stripping step caused by new interactions imparted to the refolding elements of the system especially those among the hydrophobic tails of GPI and the capturing agent of the technique. These new interactions will interrupt the kinetics of detergent stripping from the captured molecules by the stripping agent (i.e., cyclodextrins). This situation will lead to higher intermolecular hydrophobic interactions among the refolding protein intermediates leading to their higher misfolding and aggregation.
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Affiliation(s)
- Fariba Khodagholi
- Institute of Biochemistry and Biophysics, University of Tehran, P. O. Box 13145-1384, Tehran, Iran
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Kouzayha A, Besson F. GPI-alkaline phosphatase insertion into phosphatidylcholine monolayers: phase behavior and morphology changes. Biochem Biophys Res Commun 2005; 333:1315-21. [PMID: 15979580 DOI: 10.1016/j.bbrc.2005.06.049] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2005] [Accepted: 06/06/2005] [Indexed: 11/17/2022]
Abstract
GPI-anchored proteins are localized on the outer layer of plasma membranes and clustered in microdomains generally called lipid rafts. To study the interactions between the lipidic GPI-anchor of the protein and phospholipids, we used phosphatidylcholine monolayers at the air-water interface as a biomimetic membrane system and GPI-alkaline phosphatase prepared from bovine intestinal mucosa (GPI-BIAP) as an GPI-anchored protein model. The monolayer technique allowed us to define GPI-BIAP interaction with DPPC and POPC, lipids differing only by the presence of one unsaturation in their acyl chains. Meanwhile the exclusion pressures were similar for the two phospholipids, the comparison of the Langmuir isotherms (i.e., pressure/area diagrams) indicates that GPI-BIAP interacted differently with DPPC and POPC monolayers. BAM images, acquired in order to visualize the interface organization induced by GPI-BIAP incorporation, confirm these differences.
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Affiliation(s)
- Achraf Kouzayha
- Laboratoire Organisation and Dynamique des Membranes Biologiques, UMR-CNRS 5013, Université Claude Bernard Lyon I, 43 boulevard du 11 novembre 1918, F-69622 Villeurbanne Cedex, France
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Zhang L, Buchet R, Azzar G. Phosphate binding in the active site of alkaline phosphatase and the interactions of 2-nitrosoacetophenone with alkaline phosphatase-induced small structural changes. Biophys J 2005; 86:3873-81. [PMID: 15189884 PMCID: PMC1304289 DOI: 10.1529/biophysj.103.034116] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
To monitor structural changes during the binding of Pi to the active site of mammalian alkaline phosphatase in water medium, reaction-induced infrared spectroscopy was used. The interaction of Pi with alkaline phosphatase was triggered by a photorelease of ATP from the inactive P(3)-[1-(2-nitrophenyl)]ethyl ester of ATP. After photorelease, ATP was sequentially hydrolyzed by alkaline phosphatase giving rise to adenosine and three Pi. Although a phosphodiesterase activity was detected prior the photorelease of ATP, it was possible to monitor the structural effects induced by Pi binding to alkaline phosphatase. Interactions of Pi with alkaline phosphatase were evidenced by weak infrared changes around 1631 and at 1639 cm(-1), suggesting a small distortion of peptide carbonyl backbone. This result indicates that the motion required for the formation of the enzyme-phosphate complex is minimal on the part of alkaline phosphatase, consistent with alkaline phosphatase being an almost perfect enzyme. Photoproduct 2-nitrosoacetophenone may bind to alkaline phosphatase in a site other than the active site of bovine intestinal alkaline phosphatase and than the uncompetitive binding site of L-Phe in bovine intestinal alkaline phosphatase, affecting one-two amino acid residues.
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Affiliation(s)
- Le Zhang
- Universite Claude Bernard Lyon I, UFR Chimie-Biochimie UMR CNRS 5013, 69622 Villeurbanne Cedex, France
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Caseli L, Furriel RPM, de Andrade JF, Leone FA, Zaniquelli MED. Surface density as a significant parameter for the enzymatic activity of two forms of alkaline phosphatase immobilized on phospholipid Langmuir–Blodgett films. J Colloid Interface Sci 2004; 275:123-30. [PMID: 15158389 DOI: 10.1016/j.jcis.2004.01.081] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2003] [Accepted: 01/29/2004] [Indexed: 11/15/2022]
Abstract
Rat osseous plate alkaline phosphatase, a glycosylphosphatidylinositol (GPI)-anchored phosphomonohydrolase, was immobilized on Langmuir-Blodgett (LB) films. Enzyme solubilization either with polyoxyethylene-9-lauryl ether or with a glycosylphosphatidylinositol-specific phospholipase C resulted in a GPI-anchor-containing and a GPI-anchor-depleted form, respectively. Both forms were adsorbed on dimyristoylphosphatidic acid LB films and restricted to the outermost layer. The surface density and enzyme activity were determined using a quartz crystal microbalance and p-nitrophenylphosphatase activity, respectively. The detergent-solubilized form was co-spread with dimyristoylphosphatidic acid on the air/water interface and transferred to solid supports, providing an enzyme maximum surface density of 530 ng/cm2. Maximal phosphohydrolytic activity, corresponding to 43% of that observed in homogeneous medium, was obtained at a surface density of 179 ng/cm2. The phospholipase C-solubilized form was adsorbed directly from solution, reaching a maximum surface density of 1541 ng/cm2, although the phosphomonohydrolase activity was 10 times lower than that obtained for the anchor-containing form. The combined analysis of surface density and enzymatic activity suggests that the alignment of the protein molecules on the LB lipid films induced by the glycosylphosphatidylinositol anchor facilitates the access of the substrate to the active site. This access is hampered by increasing enzyme surface densities and depends on a specific orientation of the adsorbed enzyme.
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Affiliation(s)
- Luciano Caseli
- Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, 14040-901 Ribeirão Preto, São Paulo, Brazil
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