Overview of the latest developments in the role of probiotics, prebiotics and synbiotics in shrimp aquaculture.

With the growing world population, the demand for food has increased, leading to excessive and intensive breeding and cultivation of fisheries, simultaneously exacerbating the risk of disease. Recently, shrimp producers have faced major losses of stocks due to the prevalence of periodical diseases and inappropriate use of antibiotics for disease prevention and treatment, leading to bacterial resistance in shrimp, along with imposing health hazards on human consumers. Strict regulations have been placed to ban or reduce the use of prophylactic antibiotics to lessen their detrimental effects on aquatic life. Dietary and water supplements have been used as substitutes, among which probiotics, prebiotics, and synbiotics have been the most beneficial for controlling or treating bacterial, viral, and parasitic diseases in shrimp. The present analysis addresses the issues and current progress in the administration of pro-, pre-, and synbiotics as disease controlling agents in the field of shrimp farming. Furthermore, the benefits of pro-, pre-, and synbiotics and their mechanism of action have been identified such as; strengthening of immune responses, growth of antibacterial agents, alteration in gut microflora, competition for nutrients and binding sites, and enzymes related activities. Overall, this study aims to depict the antagonistic action of these supplements against a variety of pathogens and their mode of action to counter diseases and benefit shrimp species.

Interaction of organophosphate pesticide chlorpyrifos with alpha-2-macroglobulin: Biophysical and molecular docking approach.

Organophosphate class of pesticides causes neurotoxicity and carcinogenicity in humans. Once inside the human body, these pesticides often interact with plasma proteins, such as alpha-2-macroglobulin (α2M) which is the key anti-proteinase. Our work focuses on the structural and functional alteration of α2M by chlorpyrifos (CPF), a member of organophosphates. We explored the binding interaction between alpha-2-macroglobulin and CPF by using UV absorption and fluorescence spectroscopy (steady state and synchronous), circular dichroism and molecular docking approach. The functional activity of α2M was analyzed by anti-proteinase trypsin inhibitory assay which showed dose-dependent decrease in alpha-2-macroglobulin antiproteolytic potential. UV absorption studies and fluorescence quenching experiments suggested the formation of a complex between α2M and CPF. The CD spectra suggested a reduction in the beta helical (ß helix) content of α2M. Analysis of thermodynamic parameters suggested the process is spontaneous and endothermic with the ΔG and ΔH values being -5.501 kJ/mol, 11.49 kJ/mol, respectively. CPF binds with Ile-1390, Pro-1391, Leu-1392, Lys-1393, Val-1396, Lys-1397, Arg-1407, Thr-1408, Glu-1409, Val-1410, Asp-282, Glu-281 of α2M as suggested by molecular docking.

Bilirubin binding affects the structure and function of alpha-2-macroglobulin.

Bilirubin is an endogenous antioxidant that is a metabolite of the heme in red blood cells (RBC). In blood, bilirubin is associated with albumin to form a water-soluble complex, known as unconjugated bilirubin. Alpha-2-macroglobulin (α2M) is a proteinase inhibitor found in the plasma of vertebrates. In the present study, we have investigated the interaction of photo-illuminated bilirubin with serum α2M using various biophysical and thermodynamic techniques. The binding of bilirubin to α2M leads to various functional and structural changes in α2M protein. The result of ultraviolet (UV) and fluorescence spectroscopy suggests that binding of bilirubin to α2M induces a conformational change in the secondary structure of protein which was corroborated by circular dichroism (CD) and Fourier-transform infrared spectroscopy (FT-IR). This binding leads to the conversion of ß-sheet into α-helical conformation and subsequently loss in protein activity. The thermodynamic parameters of bilirubin-α2M binding indicate that the binding is exothermic, and the reaction spontaneous. Our studies show that binding of bilirubin with α2M in the presence of light induces structural and functional modifications in the protein. Bilirubin possesses multiple biological activities, including immunomodulatory property which has not been extensively explored and which may be of interest for further study.

Understanding the binding interaction between methotrexate and human alpha-2-macroglobulin: Multi-spectroscopic and computational investigation.

Methotrexate (MTX) is advised in the treatment of solid tumours, hematologic malignancies and autoimmune disorders. On reaching the circulation, 60% of MTX is bound to the proteins present in serum. Alpha-2-macroglobulin (α2M) is a plasma proteinase inhibitor with numerous functions such as binding, transportation and targeting of molecules. Our studies are the first attempt to investigate the binding interaction of pharmacologically important drug MTX, and highly abundant proteinase inhibitor- α2M. The protein functional activity assay shows 53% decrease in antiproteolytic potential of α2M upon drug interaction. The binding of MTX with α2M was studied by various biophysical methods. UV-visible absorption spectroscopy reveals hyperchromicity of α2M spectra upon drug binding. The intrinsic fluorescence spectra show quenching in fluorescence intensity of α2M and the mechanism of quenching was found to be static in nature. Far UV-CD spectra unveil slight alteration in secondary structure of α2M upon drug binding. Isothermal titration calorimetry (ITC) reveals the value of thermodynamic parameters and which affirms the binding process to be spontaneous and exothermic. Molecular docking illustrates that Asn173, Leu1298, Gly172, Lys1240, Gln1325, Ser1327, Glu913, Asn1139, Lys1236, Leu951 and Arg1297 were the key residues involved during interaction process. Molecular dynamics (MD) simulation studies suggest that MTX form a stable complex with α2M. Our study assumes importance from the fact that MTX is known to bind plasma proteins quite efficiently.

Inactivation of Alpha-2-Macroglobulin by Photo-Illuminated Gallic Acid.

Gallic acid is a naturally occurring plant polyphenol found in green tea and various fruits. Under certain conditions gallic acid exhibits pro-oxidant characteristics rather than its well known antioxidant property. In the present work, we explored the interaction of gallic acid with sheep alpha-2-macroglobulin (α2M) in the presence of light and determined the functional alteration and conformational modifications induced in α2M structure. α2M is a highly abundant homotetrameric antiproteinase glycoprotein having diverse functions. Our result suggests α2M loses almost 54% of its proteinase inhibitory activity after 2 h incubation with gallic acid in presence of light. The inactivation of α2M was due to photodynamic generation of superoxide radical and hydrogen peroxide by gallic acid. The UV/visible absorption spectra of α2M showed increase in absorbance due to complex formation with gallic acid. Intrinsic fluorescence study shows that α2M-gallic acid interaction leads to quenching of fluorescence intensity of α2M and the mechanism of quenching is found to be static in nature. Synchronous fluorescence measurements reveal that gallic acid interaction leads to change in the microenvironment around tryptophan residues of α2M. Moreover, Fourier transform infrared spectroscopy and circular dichroism spectra suggests perturbation in secondary structure of α2M. Binding parameters were investigated by spectroscopic as well as calorimetric measurements. Negative value of enthalpy change and Gibbs free energy confirms the binding process to be exothermic and spontaneous.

Insight into the molecular interaction between the anticancer drug, enzalutamide and human alpha-2-macroglobulin: Biochemical and biophysical approach.

The drug pharmacokinetics is affected upon binding with proteins, thus making drug-protein interactions crucial. This study investigated the interaction between enzalutamide and human major antiproteinase alpha-2-macroglobulin (α2M) by using multi spectroscopic and calorimetric techniques. The spectroscopic techniques such as circular dichroism (CD), intrinsic fluorescence, and UV-visible absorption were used to determine the mechanism of enzalutamide-α2M interaction. Studies on the quenching of fluorescence at three different temperatures showed that the enzalutamide-α2M complex is formed through static quenching mechanism. The change in microenvironment around tyrosine residues in protein was detected through synchronised fluorescence. The secondary structure of α2M was slightly altered by enzalutamide according to far UV-CD spectral analysis. Changes in position of amide I band in FTIR spectra further confirm the secondary structural alteration in α2M. According to thermodynamic characteristics such as fluorescence quenching and isothermal titration calorimetry (ITC), hydrogen bonds and hydrophobic interactions were involved in the interaction machanism. The ITC reiterated the exothermic and spontaneous nature of the interaction. The lower proteinase inhibitory activity of the α2M-enzalutamide conjugate as reflects the disruption of the native α2M structure upon interaction with enzalutamide.

Paediatric Emergency Medicine: Reality, Expectation, Experience, and Need for Improvements from a Low- Income Settings.

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Characterization of the binding between anti-tumor drug 5-fluorouracil and human alpha-2-macroglobulin: spectroscopic and molecular docking analyses.

5-Fluorouracil (5-FU) is a well-recognized anticancer drug used in the treatment of tumors of head, neck and breast. Drug pharmacokinetics is affected upon binding with protein, thus, making drug-protein interactions imperative to study. Present work investigates the interaction between 5-FU and human major antiproteinase-alpha-2-macroglobulin (α2M) by multi-spectroscopic, calorimetric and molecular docking techniques. UV/Visible absorption, intrinsic fluorescence and circular dichroism (CD) spectroscopic methods have been employed to unveil the mode and mechanism of 5-FU-α2M interaction. Synchronous fluorescence showed alteration in the microenvironment of tryptophan and tyrosine residues of protein. Far UV-CD spectra suggest slight alterations in the secondary structure of α2M by 5-FU. Thermodynamic parameters determined by fluorescence quenching experiments and isothermal titration calorimetry (ITC) suggested the involvement of hydrogen bonds and hydrophobic interactions. Moreover, ITC corroborate the spontaneous and exothermic nature of the interaction process. Molecular docking illustrates that 5-FU binds with moderate affinity and Asp953, Tyr1264, Lys1236, Thr1232, Tyr1323 and Leu951 were the main residues involved. Molecular dynamics simulation studies suggested that 5-FU was stabilizing the α2M structure and forming a stable complex. It was concluded that 5-FU lower the antiproteolytic activity of α2M significantly and causes disruption in the native structure and conformation of α2M.Communicated by Ramaswamy H. Sarma.

Comprehensive insight into the molecular interaction of an anticancer drug-ifosfamide with human alpha-2-macroglobulin: biophysical and in silico studies.

Ifosfamide is an active alkylating chemotherapeutic drug chemically related to nitrogen mustard. The pharmacokinetics of drugs is affected upon binding with protein, making the studies on drug-protein interaction promising. The present study investigates the interaction between ifosfamide and human antiproteinase-alpha-2-macroglobulin (α2M) by using multi-spectroscopic and in silico techniques. The UV-visible absorption, intrinsic fluorescence and circular dichroism (CD) spectroscopic methods were employed to unveil the mode and mechanism of ifosfamide-α2M interaction. Fluorescence quenching studies performed at three different temperatures indicated that ifosfamide-α2M complex formation involves static quenching. Far UV-CD spectra revealed a minor alteration in the secondary structure of α2M instigated by ifosfamide. The thermodynamic parameters determined by fluorescence quenching experiment and isothermal titration calorimetry (ITC) suggested that the complex between ifosfamide and α2M involves hydrogen bonding and hydrophobic interactions. Molecular docking illustrates that ifosfamide binds with moderate affinity to Lys1240, Asn173, Ser957, Leu955, Asp953, Lys1216 and Thr1236 residues during the interaction. Molecular dynamic (MD) simulation suggested that the ifosfamide forms a stable complex with α2M. Communicated by Ramaswamy H. Sarma.

Interaction of Human Alpha-2-Macroglobulin with Pesticide Aldicarb Using Spectroscopy and Molecular Docking.

BACKGROUND: Aldicarb is a carbamate pesticide commercially used in potato crop production. Once it enters human body, it interacts with diverse proteins and other substances. OBJECTIVE: Aldicarb is toxic to human health and it is also a cholinesterase inhibitor, which prevents the breakdown of acetylcholine in synapse. Human alpha-2-macroglobulin (α2M), is a large tetrameric glycoprotein of 720 kDa with antiproteinase activity, found abundantly in plasma. METHODS: In the present study, the interaction of aldicarb with alpha-2-macroglobulin was explored utilizing various spectroscopic techniques and molecular docking studies. RESULTS: UV-vis and fluorescence spectroscopy suggests the formation of a complex between aldicarb and α2M apparent by increased absorbance and decreased fluorescence with static quenching mode. CD spectroscopy indicates a slight change in the structure of alpha-2-macroglobulin. Docking studies confirm the interaction of aldicarb with Pro- 1391, Leu-1392, Lys-1393, Val-1396, Lys- 1397, Thr-1408, Glu-1409, Val-1410, Asp-282 and Glu-281 in the receptor binding domain at the C-terminal of the alpha 2 macroglobulin. DISCUSSION: In this work, aldicarb is shown to bind with alpha 2-macroglobulin at receptor binding domain which is the binding site for various extracellular and intracellular ligand too. Also, affecting the functional activity of the protein may lead to further physiological consequences. CONCLUSION: It is possible that aldicarb binds and compromises antiproteinase activity of α2M and binding properties by inducing changes in the secondary structure of the protein.

Quercetin-induced inactivation and conformational alterations of alpha-2-macroglobulin: multi-spectroscopic and calorimetric study.

Quercetin is a widely used bioflavonoid found in onions, grapes, berries and citrus fruits. Under certain conditions, quercetin acts as a pro-oxidant thereby generating reactive oxygen species and promoting the oxidation of molecules. Our study investigates the effect of quercetin on the structure and function of alpha-2-macroglobulin (α2M) by employing various biophysical techniques and trypsin inhibitory assay. α2M is the major antiproteinase present in the plasma of vertebrates. Results of activity assay indicated that α2M loses its 56% of inhibitory activity on treatment with quercetin in the presence of light. UV spectroscopy reveals hyper chromaticity in absorption spectra of protein on interaction with quercetin suggesting structural change. The intrinsic fluorescence studies showed quenching of α2M spectra in the presence of quercetin, and the mode of quenching was found to be static in nature. Synchronous fluorescence indicated the alteration in the microenvironment of tryptophan residues. CD and FTIR spectroscopy confirms concentration-dependent alterations in secondary structure of α2M instigated by quercetin. The magnitude of binding constant, enthalpy change, entropy change and free energy change during the interaction process was determined by isothermal titration calorimetry. Hydrogen bonding and hydrophobic interaction were the main intermolecular forces involved during the process. This study identifies and signifies the damage induced by quercetin to α2M due to its pro-oxidant action. Communicated by Ramaswamy H. Sarma.

Influence of Ascorbic Acid on the Structure and Function of Alpha-2- macroglobulin: Investigations using Spectroscopic and Thermodynamic Techniques.

BACKGROUND: Ascorbic acid is a classic dietary antioxidant which plays an important role in the body of human beings. It is commonly found in various foods as well as taken as dietary supplement. OBJECTIVE: The plasma ascorbic acid concentration may range from low, as in chronic or acute oxidative stress to high if delivered intravenously during cancer treatment. Sheep alpha-2- macroglobulin (α2M), a human α2M homologue is a large tetrameric glycoprotein of 630 kDa with antiproteinase activity, found in sheep's blood. METHODS: In the present study, the interaction of ascorbic acid with alpha-2-macroglobulin was explored in the presence of visible light by utilizing various spectroscopic techniques and isothermal titration calorimetry (ITC). RESULTS: UV-vis and fluorescence spectroscopy suggests the formation of a complex between ascorbic acid and α2M apparent by increased absorbance and decreased fluorescence. Secondary structural changes in the α2M were investigated by CD and FT-IR spectroscopy. Our findings suggest the induction of subtle conformational changes in α2M induced by ascorbic acid. Thermodynamics signatures of ascorbic acid and α2M interaction indicate that the binding is an enthalpy-driven process. CONCLUSION: It is possible that ascorbic acid binds and compromises antiproteinase activity of α2M by inducing changes in the secondary structure of the protein.

Understanding oxidants and antioxidants: Classical team with new players.

The free radical oxidants such as reactive oxygen species, reactive nitrogen species, and reactive sulfur species are produced inside cells through various metabolic processes. The body is equipped with an antioxidant defense system that guards against oxidative damage caused by these reactive oxidants and plays a major role in protecting cells from oxidative stress and damage. Antioxidants such as glutathione (GSH), thioredoxin, ascorbic acid and enzymes, for example, superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase (CAT) counter the oxidative stress and protect lipids, proteins, and DNA. Antioxidants such as tocopherols, ascorbic acid, carotenoids, flavonoids, amino acids are also natural antioxidants present in foods. There is increasing demand and availability of designer foods fortified with antioxidants and probiotics that may be important in human health. The review article presents a brief overview of oxidants and antioxidant systems inside the human body including the role of probiotics and inflammation. PRACTICAL APPLICATIONS: Antioxidants such as GSH, thioredoxin, ascorbic acid, etc. and protective enzymes, for example, SOD, GPx, CAT, etc. counter oxidative stress and protect cellular biomolecules. Antioxidants such as tocopherols, ascorbic acid, carotenoids, flavonoids, amino acids, phospholipids, and sterols are natural antioxidants found in consumed foods. They play a major role in scavenging free radical and non-radical oxidants, and protect cells from oxidative stress and damage. The importance of antioxidants can be understood from the fact that oxidative damage is now associated with a variety of diseases including cancer, neurodegeneration, diabetes, etc. Several approaches to improve human health and achieve longevity use dietary antioxidants as formulation in diet and fortified foods. Antioxidants also maintain freshness and prolonging the shelf life of food products. The fortified or designer foods that are added with antioxidant nutrients and the use of microorganisms as probiotics are increasingly available in the market as health foods and supplements.

Reduce Disease Burden of Human Schistosomiasis in Asia Through Biological Control.

Schistosomiasis is a chronic parasitic disease caused by a trematode blood fluke of the genus Schistosoma that belongs to the Schistosomatidae family. It is a neglected disease in different regions of Asia. In this review, 218 articles (between 2000 and 2017) related to the topic were collected from PubMed and Google scholar and reviewed. After thoroughly reading collected articles, due to irrelevant topic requirements, 94 articles were excluded. Articles that have data associated with Asian regions are considered. In Asia, the disease is prevalent in China, Philippines, Indonesia, Yemen, Nepal and Laos, etc. While in Pakistan, India and Bangladesh, the disease is not endemic and very few cases were reported. The disease was eliminated from Japan and Iran. The current review highlights the geographical distribution among Asian countries, transmission patterns, diagnosis, control strategies based on the use of anthelmintic plants and management practices implemented in Asia for the control of schistosomiasis. However, new implementations to treat schistosomiasis in humans should be proved to eliminate the disease finally in the future. This review emphasizes the biological control of schistosomiasis for the eradication of the disease from Asia in the near future.

Biophysical analysis of interaction between curcumin and alpha-2-macroglobulin.

Alpha-2-macroglobulin (α2M) is large glycoprotein present in the body fluids of vertebrates. It is an antiproteinase that inhibits a broad spectrum of proteases without the direct blockage of the protease active site. Curcumin, a yellow spice commonly used in India and several Asian countries, is reported to have anti-tumor and anti-inflammatory effects because of its antioxidant properties. In the present study, we have explored the interaction of curcumin with α2M using various technique such as antiproteinase activity assay, spectroscopy. Changes in the secondary structure of α2M following interaction with curcumin was investigated by CD and FT-IR spectroscopy. Thermodynamics of curcumin-α2M binding were also analyzed by isothermal titration calorimetry to identify the number of binding sites, changes in enthalpy, entropy and Gibbs free energy changes for this interaction. Thermodynamics parameters reveal that the binding is exothermic in nature. Our results suggest that the binding of curcumin with α2M induces a conformational change in the native form of protein that compromises its anti-proteinase activity. This exothermic and spontaneous interaction leads to alteration in the ß-sheet content of the protein leading to subtle changes in conformational status of the protein leading possibly to loss in the antiproteinase potential of the inhibitor.

Deciphering the binding of dutasteride with human alpha-2-macroglobulin: Molecular docking and calorimetric approach.

Dutasteride is a pharmacologically important drug employed to treat prostate cancer. Alpha-2-macroglobulin (α2M) is the primary proteinase inhibitor and is abundant in vertebrate plasma. Previous studies have shown that α2M levels were down regulated in prostate cancer. Our results of functional assay shows 50% decrease in the antiproteolytic potential ofα2Mupon its interaction with dutasteride. Fluorescence quenching revealed that dutasteride binds with α2M via static mechanism, resulting in the formation of dutasteride-α2M complex. Synchronous fluorescence studies suggest alteration in the microenvironment around tryptophan residues. Changes in the UV-visible spectra hints at formation of complex between the drug and protein. Secondary structural perturbations in α2M are confirmed by circular dichroism studies. Molecular docking discloses the involvement of hydrogen bonding during the interaction process and suggests the site of interaction of dutasteride on α2M monomer as Asn173, Lys171, Asp1178, Lys1236, His1182, Lys1177, Ser1180 and Lys1240.Isothermal titration calorimetry affirms the binding process to be spontaneous and exothermic. The results of this study may potentially be important should it be shown that dutasteride interacts with α2M under physiological conditions.

Insight into the interactions of proteinase inhibitor- alpha-2-macroglobulin with hypochlorite.

Hypochlorous acid (HOCl), an active bleaching agent is one of the major oxidant produced by neutrophils under physiological conditions. It is among one of the most potent reactive oxygen species (ROS) which causes oxidation of biomolecules. Treatment of proteins with hypochlorite results in direct oxidative damage to the protein. Alpha-2-macroglobulin (α2M) is a major proteinase inhibitor that can inhibit proteinase of any kind regardless of their specificity and catalytic mechanism. The proteinase-antiproteinase balance plays an important role in mediating inflammation associated tissue destruction. In this paper, we intend to study hypochlorite induced modifications in proteinase inhibitor- α2M via biophysical techniques such as absorption spectroscopy, fluorescence spectroscopy, circular dichroism (CD), fourier transform infrared spectrometry (FTIR) and isothermal titration calorimetry (ITC). It was found that hypochlorite decreases the anti-proteolytic potential and causes inactivation of sheep α2M. It also causes structural and functional change in sheep α2M as evident by UV-Visible absorption spectroscopy and fluorescence measurements. Change in secondary structure of α2M was confirmed by CD and FTIR. Thermodynamics parameters such as entropy change (ΔS), enthalpy change (ΔH), Gibbs free energy change (ΔG) and the number of binding sites (N) of α2M-HOCl binding in solutions were determined by ITC. Moreover, it was found that binding of HOCl with α2M was exothermic in nature.

Interaction of anti-cancer drug-cisplatin with major proteinase inhibitor-alpha-2-macroglobulin: Biophysical and thermodynamic analysis.

Alpha-2-macroglobulin is a multifunctional, highly abundant, plasma protein which reacts with a wide variety of molecules and drugs including cisplatin. Cisplatin is commonly used anticancer drug widely used for treatment of testicular, bladder, ovarian, head and neck, lung and cervical cancers. This study is designed to examine the interaction of cisplatin with human alpha-2-macroglobulin through various biophysical techniques and drug binding through molecular modeling. Cisplatin alters the function of alpha-2-macroglobulin and the thiolesters are most likely the reactive sites for cisplatin. Our result suggests that cisplatin decreases the antiproteolytic potential and causes structural and functional change in human alpha-2-macroglobulin as evident by absorption and fluorescence spectroscopy. Change in secondary structure of alpha-2-macroglobulin was confirmed by CD and FTIR. Thermodynamics parameters such as entropy (ΔS), enthalpy (ΔH) and Gibb's free energy changes (ΔG) along with number of binding sites (N) of alpha-2-macroglobulin-cisplatin binding in solutions were determined by isothermal titration calorimetry (ITC). It was found that binding of cisplatin with alpha-2-macroglobulin was exothermic in nature. The interaction of drug with alpha-2-macroglobulin in the plasma could lead to structural alterations in the conformational status of alpha-2-macroglobulin resulting in its functional inactivation.

Exploring the interaction of anti-androgen drug-bicalutamide with human alpha-2-macroglobulin: A biophysical investigation.

Bicalutamide (BCT), a drug used in the treatment of prostate cancer, antagonises the actions of androgens, at the receptor level, thereby inhibiting the growth of prostate tumours. Alpha-2-macroglobulin (α2M), a pan-proteinase inhibitor, inhibits proteinase, regardless of specificity and catalytic mechanism. α2M is deficient in patients of advanced prostate cancer with bone metastases. Our studies explored the interaction of BCT with α2M and analysed the BCT induced structural alteration to the α2M. The result suggests that BCT decreases the antiproteolytic potential and causes structural and functional change in human α2M. UV-visible absorption spectroscopy confirms the formation of α2M-BCT complex. Fluorescence analysis shows significant quenching in fluorescence intensity of α2M upon binding with BCT. Synchronous fluorescence result suggests the interaction of BCT with α2M changed the microenvironment around tyrosine residues. Secondary structure of α2M also undergoes a slight change upon complexation with the drug as evident by shift in negative ellipticity in far UV CD spectroscopy. FTIR results confirm the alteration in secondary structure of α2M upon drug interaction. Molecular docking studies show that BCT bind to a monomer of α2M primarily through hydrophobic force. Thermodynamics parameters were determined by isothermal titration calorimetry found that the binding was exothermic in nature.

Binding interaction of sheep alpha-2-macroglobulin and tannic acid: A spectroscopic and thermodynamic study.

Tannic acid is a polyphenol found in plant species commonly consumed by ruminants. It works as an important molecule in plant defense system to fight against environmental stressors. Tannic acid has number of effects on animals and humans. An attempt has been made to study the interaction of tannic acid with alpha-2-macroglobulin (α2M). α2M is a large tetrameric glycoprotein which function as a key serum anti-proteinase under physiological conditions. In the present study we explored the tannic acid-α2M interaction by number of spectroscopic techniques such as UV, fluorescence, CD and FTIR along with isothermal titration calorimetry. CD and FT-IR spectroscopy were mainly used to study the secondary structural change induced in the antiproteinase. Analysis of activity shows the antiproteolytic potential of protein was compromised. Data of UV spectroscopy shows formation of α2M-tannic acid complex. The thermodynamic signatures of this interaction reveals hydrogen bonding played a major role in the binding of α2M-tannic acid. Analysis of CD and FTIR results suggest a minor conformational change in α2M on tannic acid binding. Overall, tannic acid induces subtle conformation change in α2M structure resulting the loss of its proteinase inhibitory activity.