1
|
Gomari MM, Rostami N, Faradonbeh DR, Asemaneh HR, Esmailnia G, Arab S, Farsimadan M, Hosseini A, Dokholyan NV. Evaluation of pH change effects on the HSA folding and its drug binding characteristics, a computational biology investigation. Proteins 2022; 90:1908-1925. [DOI: 10.1002/prot.26386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2021] [Revised: 04/24/2022] [Accepted: 04/26/2022] [Indexed: 11/12/2022]
Affiliation(s)
- Mohammad Mahmoudi Gomari
- Student Research Committee, Iran University of Medical Sciences Tehran Iran
- Department of Medical Biotechnology, Faculty of Allied Medicine Iran University of Medical Sciences Tehran Iran
| | - Neda Rostami
- Department of Chemical Engineering, Faculty of Engineering Arak University Arak Iran
| | - Davood Rabiei Faradonbeh
- Department of Medical Biotechnology School of Advanced Technologies in Medicine, Tehran University of Medical Sciences Tehran Iran
| | - Hamid Reza Asemaneh
- Polymer Research Center, Department of Chemical Engineering Razi University Kermanshah Iran
| | - Giti Esmailnia
- Department of Medical Biotechnology, Faculty of Allied Medicine Iran University of Medical Sciences Tehran Iran
| | - Shahriar Arab
- Department of Biophysics School of Biological Sciences, Tarbiat Modares University Tehran Iran
| | - Marziye Farsimadan
- Department of Biology, Faculty of Sciences University of Guilan Rasht Iran
| | - Arshad Hosseini
- Department of Medical Biotechnology, Faculty of Allied Medicine Iran University of Medical Sciences Tehran Iran
| | - Nikolay V. Dokholyan
- Department of Pharmacology, Department of Biochemistry & Molecular Biology Pennsylvania State University College of Medicine Hershey Pennsylvania USA
| |
Collapse
|
2
|
Terrill JR, Al-Mshhdani BA, Duong MN, Wingate CD, Abbas Z, Baustista AP, Bettis AK, Balog-Alvarez CJ, Kornegay JN, Nghiem PP, Grounds MD, Arthur PG. Oxidative damage to urinary proteins from the GRMD dog and mdx mouse as biomarkers of dystropathology in Duchenne muscular dystrophy. PLoS One 2020; 15:e0240317. [PMID: 33031394 PMCID: PMC7544076 DOI: 10.1371/journal.pone.0240317] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Accepted: 09/23/2020] [Indexed: 12/22/2022] Open
Abstract
Duchenne muscular dystrophy (DMD) is a lethal, X-chromosome linked muscle-wasting disease affecting about 1 in 3500–6000 boys worldwide. Myofibre necrosis and subsequent loss of muscle mass are due to several molecular sequelae, such as inflammation and oxidative stress. We have recently shown increased neutrophils, highly reactive oxidant hypochlorous acid (HOCl) generation by myeloperoxidase (MPO), and associated oxidative stress in muscle from the GRMD dog and mdx mouse models for DMD. These findings have led us to hypothesise that generation of HOCl by myeloperoxidase released from neutrophils has a significant role in dystropathology. Since access to muscle from DMD patients is limited, the aim of this study was to develop methods to study this pathway in urine. Using immunoblotting to measure markers of protein oxidation, we show increased labelling of proteins with antibodies to dinitrophenylhydrazine (DNP, oxidative damage) and DiBrY (halogenation by reactive oxidants from myeloperoxidase) in GRMD and mdx urine. A strong positive correlation was observed between DiBrY labelling in dog urine and muscle. A strong positive correlation was also observed when comparing DNP and DiBrY labelling (in muscle and urine) to markers of dystropathology (plasma creatine kinase) and neutrophil presence (muscle MPO). Our results indicate the presence of neutrophil mediated oxidative stress in both models, and suggest that urine is a suitable bio-fluid for the measurement of such biomarkers. These methods could be employed in future studies into the role of neutrophil mediated oxidative stress in DMD and other inflammatory pathologies.
Collapse
Affiliation(s)
- Jessica R. Terrill
- School of Molecular Sciences, The University of Western Australia, Perth, Australia
- * E-mail:
| | - Basma A. Al-Mshhdani
- School of Molecular Sciences, The University of Western Australia, Perth, Australia
| | - Marisa N. Duong
- School of Molecular Sciences, The University of Western Australia, Perth, Australia
| | - Catherine D. Wingate
- School of Molecular Sciences, The University of Western Australia, Perth, Australia
| | - Zahra Abbas
- School of Molecular Sciences, The University of Western Australia, Perth, Australia
| | - Angelo P. Baustista
- School of Molecular Sciences, The University of Western Australia, Perth, Australia
| | - Amanda K. Bettis
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas, United States of America
| | - Cynthia J. Balog-Alvarez
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas, United States of America
| | - Joe N. Kornegay
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas, United States of America
| | - Peter P. Nghiem
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas, United States of America
| | - Miranda D. Grounds
- School of Human Sciences, The University of Western Australia, Perth, Australia
| | - Peter G. Arthur
- School of Molecular Sciences, The University of Western Australia, Perth, Australia
| |
Collapse
|
3
|
|
4
|
Santra MK, Banerjee A, Rahaman O, Panda D. Unfolding pathways of human serum albumin: Evidence for sequential unfolding and folding of its three domains. Int J Biol Macromol 2005; 37:200-4. [PMID: 16324740 DOI: 10.1016/j.ijbiomac.2005.10.009] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2005] [Revised: 10/26/2005] [Accepted: 10/26/2005] [Indexed: 11/19/2022]
Abstract
Human serum albumin (HSA) contains three alpha-helical domains (I-III). The unfolding process of these domains was monitored using covalently bound fluorescence probes; domain I was monitored by N-(1-pyrene)maleimide (PM) conjugated with cys-34, domain II was monitored by the lone tryptophan residue and domain III was followed by p-nitrophenyl anthranilate (NPA) conjugated with Tyrosine-411 (Tyr-411). Using domain-specific probes, we found that guanidium hydrochloride-induced unfolding of HSA occurred sequentially. The unfolding of domain II preceded that of domain I and the unfolding of domain III followed that of domain I. In addition, the domains I and III refolded within the dead time of the fluorescence recovery experiment while the refolding of domain II occurred slowly. The results suggest that individual domain of a multi-domain protein can fold and unfold sequentially.
Collapse
Affiliation(s)
- Manas Kumar Santra
- School of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai 400076, India.
| | | | | | | |
Collapse
|
5
|
Hashimoto S, Yabusaki T, Takeuchi H, Harada I. Structure and ligand-binding modes of human serum albumin studied by UV resonance raman spectroscopy. ACTA ACUST UNITED AC 1995. [DOI: 10.1002/bspy.350010603] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
6
|
Dubois N, Lapicque F, Magdalou J, Abiteboul M, Netter P. Stereoselective binding of the glucuronide of ketoprofen enantiomers to human serum albumin. Biochem Pharmacol 1994; 48:1693-9. [PMID: 7980637 DOI: 10.1016/0006-2952(94)90453-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Since acyl glucuronides are known to undergo deconjugation, especially in the presence of human serum albumin (HSA), only a few reports have described their reversible binding to plasma proteins. The aim of this study was to investigate the reversible binding of R and S ketoprofen glucuronides to HSA by a rapid technique, such as ultraviolet circular dichroism. Binding of R ketoprofen glucuronide only induced an extrinsic Cotton effect at 340 nm. Scatchard plot analysis revealed that R ketoprofen and its glucuronide are bound to one site of albumin with an association constant of 28.1 x 10(4) and 6.1 x 10(4) M-1, respectively. Modification of one tyrosine residue by diisopropylfluorophosphate prevented the access of ligands to sites I and II of albumin, and also fully inhibited the binding of R ketoprofen and that of its conjugate. Displacement experiments with specific probes of albumin binding sites suggested that R ketoprofen and the glucuronide are bound to site II rather than site I. However, R ketoprofen was not displaced by its conjugate. S ketoprofen glucuronide is also bound to HSA, since it decreased the binding of the antipode conjugate. However, the binding of this metabolite to albumin did not induce an extrinsic Cotton effect large enough to determine the binding constants. D-Glucuronic acid did not bind to sites I or II of albumin. This moiety is likely responsible for the lower affinity of HSA for the R ketoprofen glucuronide when compared to that for R ketoprofen, due to the hydrophilicity and/or the bulkiness of this group.
Collapse
Affiliation(s)
- N Dubois
- Laboratoire de Pharmacologie, URA CNRS 1288, Faculté de Médecine, Nancy, France
| | | | | | | | | |
Collapse
|
7
|
Williams AM, Dickinson RG. Studies on the reactivity of acyl glucuronides--VI. Modulation of reversible and covalent interaction of diflunisal acyl glucuronide and its isomers with human plasma protein in vitro. Biochem Pharmacol 1994; 47:457-67. [PMID: 8117313 DOI: 10.1016/0006-2952(94)90176-7] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Acyl glucuronide conjugates are chemically reactive metabolites which can undergo hydrolysis, rearrangement (isomerization via acyl migration) and covalent binding reactions with protein. The present study was undertaken to identify factors modulating the reactivity of diflunisal acyl glucuronide (DAG) with human serum albumin (HSA) in vitro, by comprehensively evaluating the interplay of the three pathways above when DAG and a mixture of its 2-, 3- and 4-isomers (iso-DAG) were incubated with protein. Buffer, plasma, fraction V HSA, fatty acid-free HSA, globulin-free HSA and fatty acid- and globulin-free HSA were investigated at pH 7.4 and 37 degrees, each in the absence and presence of warfarin, diazepam and diflunisal (DF) as reversible binding competitors. DAG and iso-DAG were highly reversibly bound (ca. 98-99.5%) in plasma and HSA solutions. The binding was primarily at the benzodiazepine site, since displacement occurred in the presence of diazepam and fatty acids but not warfarin. DAG degradation, via rearrangement, hydrolysis and covalent adduct formation (in that order of quantitative importance), was retarded in plasma and HSA solutions compared to buffer. The protective effect of protein was afforded by the high reversible binding to the (non-catalytic) benzodiazepine site. The warfarin site appeared to be catalytic for DAG hydrolysis, whereas rearrangement appeared to be hydroxide ion-catalysed only. In contrast to DAG, iso-DAG degradation was greatly accelerated in the presence of protein, through both covalent binding and catalysis of hydrolysis. Covalent binding via DAG was increased in the presence of warfarin but decreased in the presence of diazepam, DF and fatty acids. The opposite effects were found for covalent binding via iso-DAG. The data suggest that covalent binding of DF to HSA via DAG and iso-DAG occurs by different mechanisms (presumably transacylation and glycation, respectively) at different sites (benzodiazepine and warfarin, respectively) whereas reversible binding occurs primarily at the same site (benzodiazepine).
Collapse
Affiliation(s)
- A M Williams
- Department of Medicine, University of Queensland, Royal Brisbane Hospital, Australia
| | | |
Collapse
|
8
|
Zia-Amirhosseini P, Spahn-Langguth H, Benet LZ. Bioactivation by glucuronide-conjugate formation. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 1994; 27:385-97. [PMID: 8068561 DOI: 10.1016/s1054-3589(08)61040-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
|
9
|
Maruyama T, Lin CC, Yamasaki K, Miyoshi T, Imai T, Yamasaki M, Otagiri M. Binding of suprofen to human serum albumin. Role of the suprofen carboxyl group. Biochem Pharmacol 1993; 45:1017-26. [PMID: 8461031 DOI: 10.1016/0006-2952(93)90245-r] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The binding of suprofen (SP), a non-steroidal anti-inflammatory drug of the arylpropionic acid class, and its methyl ester derivative (SPM) to human serum albumin (HSA) was studied by dialysis and spectroscopic techniques. In spite of the remarkable differences in the physicochemical properties of SP and SPM, the binding of each molecule to HSA was quantitatively very similar. Thermodynamic analysis suggests that the interaction of SP with HSA may be caused by electrostatic as well as hydrophobic forces, whereas the interactions with SPM may be explained by hydrophobic and van der Waals forces. Similarities in the difference UV absorption spectra between ligand-detergent micelle and -HSA systems indicate that the SP and SPM molecules are inserted into a hydrophobic crevice on HSA. The same studies suggest that the carboxyl group of SP interacts with a cationic sub-site which is closely associated with the SP binding site. Proton relaxation rate measurements indicate that the thiophen ring and propanoate portion of the SP molecule is the major binding site for HSA. The locations of SP and SPM binding sites were identified by using fluorescence probes which bind to a known site on HSA. The displacement data implied that SP primarily binds to Site II, while the high affinity site of SPM as well as low affinity site of SP are at the warfarin binding site in the Site I area. From binding data with chemically modified HSA derivatives, it is likely that highly reactive tyrosine (Tyr) and lysine (Lys) residues, which may be Tyr-411 and Lys-195, are specifically involved in SP binding. In contrast, these two residues are clearly separated from the SPM binding site. The binding of SP and SPM is independent of conformational changes on HSA that accompany N-B transition. There is evidence that the carboxyl group may play a crucial role in the high affinity binding processes of SP to HSA.
Collapse
Affiliation(s)
- T Maruyama
- Faculty of Pharmaceutical Sciences, Kumamoto University, Japan
| | | | | | | | | | | | | |
Collapse
|
10
|
Abstract
The fluorescent probes warfarin and dansylsarcosine are known to selectively interact with binding sites I and II, respectively, on human albumin. This paper investigates whether similar binding sites exist on bovine, dog, horse, sheep and rat albumins. Binding sites on albumins were studied by: (1) displacement of warfarin and dansylsarcosine by site I (phenylbutazone) and site II (diazepam) selective ligands; (2) the effects of non-esterified fatty acids (carbon chain lengths: C5-C20) and changes in pH (6-9) on the fluorescence of warfarin and dansylsarcosine; and (3) the ability of site selective ligands to inhibit hydrolysis of 4-nitrophenyl acetate. For bovine, dog, horse, human and sheep albumins the fluorescence of bound warfarin and dansylsarcosine was selectively decreased by phenylbutazone and diazepam, respectively. For these albumins medium chain fatty acids (C1-C12) reduced the fluorescence of dansylsarcosine (maximum inhibition with C9) whereas long chain acids (C12-C20) enhanced the fluorescence of warfarin (maximum increases with C12). In addition, changes in pH from 6 to 9 increased the fluorescence of warfarin and although site I ligands (warfarin/phenylbutazone) had no pronounced effects on 4-nitrophenyl acetate hydrolysis, site II ligands (dansylsarcosine/diazepam) significantly inhibited this reaction. Rat albumin behaved differently from the other albumins studied in that the C12-C20 fatty acids and changes in pH did not enhance the fluorescence of warfarin. Moreover, the differential effects of site I and site II ligands on the fluorescence of warfarin/dansylsarcosine and hydrolysis of 4-nitrophenyl acetate were less apparent with rat albumin. The results suggest bovine, dog, horse and sheep albumins have binding sites for warfarin and dansylsarcosine with similar properties to sites I and II on human albumin. By contrast, the warfarin binding site and to a lesser degree the dansylsarcosine site, of rat albumin have different characteristics from these sites on the other albumins studied.
Collapse
|
11
|
Noctor TA, Wainer IW. The in situ acetylation of an immobilized human serum albumin chiral stationary phase for high-performance liquid chromatography in the examination of drug-protein binding phenomena. Pharm Res 1992; 9:480-4. [PMID: 1495892 DOI: 10.1023/a:1015884112039] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The in situ modification of an immobilized human serum albumin (HSA) high-performance liquid chromatographic chiral stationary phase by p-nitrophenyl acetate is reported. This procedure, which is thought to affect primarily a single reactive tyrosine residue within the protein structure, influenced the chromatographic retention and enantioselectivity factors of a wide range of solutes. For certain solutes, increases in both capacity factor and chiral resolution were observed. Ultrafiltration studies on representative test solutes using free HSA, treated in a similar manner to the immobilized protein, gave similar results as the chromatographic observations, indicating that the latter effects are not artifactual results of immobilization. The effect of the modification of HSA on the binding behavior of drugs reportedly sharing the site predominantly affected by the derivatization, namely, the indole-benzodiazepine binding site, varied greatly. This observation suggests that the affected binding area is not a single, tightly structurally defined site.
Collapse
Affiliation(s)
- T A Noctor
- Department of Oncology, McGill University, Montréal, Canada
| | | |
Collapse
|
12
|
Spahn-Langguth H, Benet LZ. Acyl glucuronides revisited: is the glucuronidation process a toxification as well as a detoxification mechanism? Drug Metab Rev 1992; 24:5-47. [PMID: 1555494 DOI: 10.3109/03602539208996289] [Citation(s) in RCA: 301] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- H Spahn-Langguth
- Department of Pharmacy, University of California, San Francisco 94143-0446
| | | |
Collapse
|
13
|
|
14
|
Pinquier JL, Urien S, Chaumet-Riffaud P, Tillement JP. Differences in the serum binding determinants of isradipine and darodipine--consequences for serum protein binding in various diseases. Br J Clin Pharmacol 1989; 28:587-92. [PMID: 2531607 PMCID: PMC1380020 DOI: 10.1111/j.1365-2125.1989.tb03546.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
1. Serum protein binding of isradipine and darodipine, and serum concentrations of alpha 1-acid glycoprotein (AAG), albumin (HSA) and non-esterified fatty acids (NEFA) were measured in three groups of patients, I: healthy subjects (n = 20); II: patients with inflammatory disorders (n = 15) and III: patients with hepatic insufficiency (n = 17). 2. AAG was increased significantly in group II patients (P less than 0.001) and decreased in group III patients (P less than 0.001); HSA was decreased significantly in group II and group III patients (P less than 0.001). 3. The free percentage of isradipine was decreased significantly in group II patients (P less than 0.05) and increased in group III patients (P less than 0.05) and multivariate analysis showed that these variations were inversely related to changes in AAG concentration. 4. The free percentage of darodipine was increased significantly in group II and III patients (P less than 0.05) due to a decrease in HSA concentration, as shown by multivariate analysis. 5. The changes in free serum percentages of isradipine and darodipine were inversely related to concomitant changes in the concentration of the serum protein for which they showed the highest affinity, AAG for isradipine and HSA for darodipine, respectively. 6. The unexplained variability in the binding data was greater when AAG was the major determinant of binding (isradipine).
Collapse
Affiliation(s)
- J L Pinquier
- Département de Pharmacologie, Faculté de Médecine de Paris XII, France
| | | | | | | |
Collapse
|
15
|
Otagiri M, Masuda K, Imai T, Imamura Y, Yamasaki M. Binding of pirprofen to human serum albumin studied by dialysis and spectroscopy techniques. Biochem Pharmacol 1989; 38:1-7. [PMID: 2910295 DOI: 10.1016/0006-2952(89)90141-x] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The interaction of pirprofen with human serum albumin (HSA) was investigated by equilibrium dialysis and spectroscopic (UV absorption, fluorescence, CD, NMR) techniques. It was found that HSA binds pirprofen nonstereospecifically. The binding of pirprofen depends upon the N-B conformational change of albumin. Chloride ions appear to displace the drug from its binding site. The thermodynamic parameters suggest that the interaction may be explained by electrostatic as well as hydrophobic forces. The absorption spectral changes which accompanied the binding of pirprofen to HSA implied that the aromatic portion of drugs was inserted into the hydrophobic crevice in the protein, while the carboxyl group of the drug interacted with a cationic site on the albumin surface. The NMR data indicated that the pyrroline ring and propionic acid parts may be the major binding site for HSA. A specific binding site for pirprofen on the HSA was found to be site II, benzodiazepine site, using fluorescence probes and drug markers. In addition, from the binding data with modified HSA, it seems that Tyr-411 is specifically involved in pirprofen binding.
Collapse
Affiliation(s)
- M Otagiri
- Faculty of Pharmaceutical Sciences, Kumamoto University, Japan
| | | | | | | | | |
Collapse
|
16
|
Wells DS, Janssen FW, Ruelius HW. Interactions between oxaprozin glucuronide and human serum albumin. Xenobiotica 1987; 17:1437-49. [PMID: 3439193 DOI: 10.3109/00498258709044004] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
1. The first step in the interaction between oxaprozin glucuronide and human serum albumin (HSA) is formation of a reversible complex which then leads to the following reactions; (a) acyl migration of the aglycone from position 1 to positions 2, 3 and 4 of the glucuronic acid moiety; (b) hydrolysis of the glycosidic bond; and (c) covalent binding of oxaprozin to the HSA molecule. The isomers of oxaprozin glucuronide formed in (a) and the covalently bonded drug in (c) are also hydrolyzed to oxaprozin. 2. Oxaprozin and ligands known to bind at Site II as classified by Sudlow et al. (1976), also called the benzodiazepine binding site (Müller and Wollert 1975), inhibit these reactions with oxaprozin glucuronide, while ligands which are known to bind at other sites on HSA do not. 3. Modification of a single tyrosine residue, located within Site II, with tetranitromethane, diisopropylfluorophosphate, and p-nitrophenylacetate causes significant reduction of the covalent binding of oxaprozin to HSA. 4. Tetranitromethane modification of HSA decreases all three reactions, while not inhibiting the formation of the reversible complex, indicating that the tyrosine located in Site II (tyr-411)acts as the nucleophile in these reactions. 5. Chemical modification of lysine residues has only a small effect on the reactions while modification of the lone free sulphhydryl (cys) in HSA has no effect.
Collapse
Affiliation(s)
- D S Wells
- Wyeth Laboratories, Philadelphia, PA 19101-8299
| | | | | |
Collapse
|
17
|
Dirr HW, Schabort JC. Characterization of the aflatoxin B1-binding site of rat albumin. BIOCHIMICA ET BIOPHYSICA ACTA 1987; 913:300-7. [PMID: 3109487 DOI: 10.1016/0167-4838(87)90139-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
A fluorescence-enhancement method was used to investigate the non-covalent interaction between aflatoxin B1 and rat albumin. Solvent-induced shifts in the emission spectrum of aflatoxin B1 provided evidence that the aflatoxin B1-binding site of rat albumin is a highly nonpolar environment. A dissociation constant of 20 microM was determined at 20 degrees C. The possibility that aflatoxin B1 binds one of the three major drug sites of albumin was investigated by ligand-displacement experiments. Mechanisms whereby marker ligands displace aflatoxin B1 were further investigated by comparing the experimental binding parameters with those derived theoretically, assuming competitive binding. The results indicate that: aflatoxin B1 and phenylbutazone compete for a common high-affinity site on rat albumin; high-affinity binding of aflatoxin B1 and site-II marker ligands takes place independently; aflatoxin B1 does not compete with either cholate or warfarin for the same high-affinity site, but the simultaneous binding of warfarin or cholate negatively modulates the binding of aflatoxin B1 to albumin. Fluorescence energy-transfer studies show that the lone tryptophan residue, Trp-214, is not associated with the aflatoxin B1-binding site.
Collapse
|
18
|
Ruelius HW, Kirkman SK, Young EM, Janssen FW. Reactions of oxaprozin-1-O-acyl glucuronide in solutions of human plasma and albumin. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1986; 197:431-41. [PMID: 3766273 DOI: 10.1007/978-1-4684-5134-4_42] [Citation(s) in RCA: 36] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Hydrolysis and rearrangement (isomerization by acyl migration) of oxaprozin glucuronide are greatly accelerated by plasma and human serum albumin. Albumin accounts for all the hydrolytic activity in plasma and no esterase is involved. The isomeric esters formed by rearrangement are also good substrates for the hydrolysis reaction. Another reaction between oxaprozin glucuronide and albumin leads to covalent binding of the aglycone. Similar reactions leading to covalent binding have been described for other acyl glucuronides by several investigators. In the case of oxaprozin, there is little or no potential for biological significance of covalent binding because the reaction is almost entirely inhibited by low concentrations of the drug. All three reactions are pH dependent but not to the same extent. They can be considered to be transacylations to the hydroxyl ion (hydrolysis), to a different OH-group of the glucuronic acid moiety (rearrangement) or to a nucleophilic group on the albumin molecule (covalent binding). All three reactions are greatly inhibited by the same compounds suggesting a common reaction site. This site has certain features in common with the indole or benzodiazepine binding site of human serum albumin. A scheme is proposed in which the first step is reversible binding of the acyl glucuronide to this site in analogy to the known reversible binding of reactive esters (such as p-nitrophenyl acetate) to the same site. All three reactions are inhibited by compounds such as naproxen and decanoic acid which are known to also inhibit the acylation of albumin by reactive esters and the reversible binding of benzodiazepines.
Collapse
|
19
|
Hagag N, Birnbaum ER, Darnall DW. Resonance energy transfer between cysteine-34, tryptophan-214, and tyrosine-411 of human serum albumin. Biochemistry 1983; 22:2420-7. [PMID: 6860638 DOI: 10.1021/bi00279a018] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Reaction of p-nitrophenyl anthranilate with human serum albumin at pH 8.0 results in esterification of a single anthraniloyl moiety with the hydroxyl group of tyrosine-411. The absorption spectrum of the anthraniloyl group overlaps the fluorescence emission of the single tryptophan residue at position 214. This study complements that of the preceding paper [Suzukida, M., Le, H. P., Shahid, F., McPherson, R. A., Birnbaum, E.R., & Darnall, D. W. (1983) Biochemistry (preceding paper in this issue)] where an azomercurial group was introduced at cysteine-34. Anthraniloyl fluorescence was also quenched by the azomercurial absorption at Cys-34. Thus measurement of resonance energy transfer between these three sites allowed distances to be measured between Cys-34 in domain I, Trp-214 in domain II, and Tyr-411 in domain III of human serum albumin. At pH 7.4 in 0.1 M phosphate the Trp-214 leads to Tyr-411, Tyr-411 leads to Cys-34, and Trp-214 leads to Cys-34 distances were found to be 25.2 +/- 0.6, 25.2 +/- 2.1, and 31.8 +/- 0.8 A, respectively.
Collapse
|
20
|
Ohta N, Kurono Y, Ikeda K. Esterase-like activity of human serum albumin II: reaction with N-trans-cinnamoylimidazoles. J Pharm Sci 1983; 72:385-8. [PMID: 6864475 DOI: 10.1002/jps.2600720416] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
To elucidate the details of the esterase activity of human serum albumin, the reaction of N-trans-cinnamoylimidazoles with albumin was investigated kinetically at various pHs at 25 degrees. The reaction consisted of the acylation of albumin (probably the tyrosine-411 residue) by the substrate and the deacylation of cinnamoyl-albumin. The acylation was approximately 10--100-fold faster than the spontaneous hydrolysis of the substrate over the pH range examined. The pH profile for the deacylation rate constant indicated the participation of a group having a pKa of approximately 9.4. The deacylation was subjected to the effect of deuterium oxide. The electron-withdrawing substituent facilitated the deacylation; the Hammett rho value was 1.63. These results suggest that the deacylation proceeded via general base catalysis by this group.
Collapse
|
21
|
Fehske KJ, Müller WE, Wollert U. The location of drug binding sites in human serum albumin. Biochem Pharmacol 1981; 30:687-92. [PMID: 7018498 DOI: 10.1016/0006-2952(81)90151-9] [Citation(s) in RCA: 256] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
|