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Wu CL, Chang SJ, Tori M, Furuta H, Sumida A, Asakawa Y. Tridensenal, A Sesquiterpene of Novel Skeleton from the Taiwanese LiverwortBazzania Tridens. J CHIN CHEM SOC-TAIP 2013. [DOI: 10.1002/jccs.199000052] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Hakozaki M, Ono K, Suzuki T, Hata H, Mori T, Kochi H. Characterization of rainbow trout branched-chain alpha-keto acid dehydrogenase complex: inter-domain segments of the E2 component affect the overall activity. Comp Biochem Physiol B Biochem Mol Biol 2002; 132:433-42. [PMID: 12031470 DOI: 10.1016/s1096-4959(02)00061-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Branched-chain alpha-keto acid dehydrogenase complex (BCKADH) contains decarboxylase (E1), dihydrolipoyl transacylase (E2), and dihydrolipoyl dehydrogenase (E3) as catalytic components. BCKADH purified from rainbow trout (Oncorhynchus mykiss) liver was comparable with mammalian BCKADH in various enzymatic characteristics, but less efficient in catalyzing the overall reaction. The trout E2 subunit was larger than the mammalian subunit and rather similar to the chicken one in relative molecular mass on SDS-PAGE, whereas the E1 component was similar between trout and mammalian both in relative molecular mass of its alpha and beta subunits and in the catalytic activity. Trout E2 cDNA cloning and nucleotide sequencing revealed that the mature trout E2 subunit consists of 435 residues, and possesses 14 additional residues compared with mammalian E2. Eleven of these are localized in two interdomain segments as two sequences with two and nine residues, respectively. Trout E2 was inferior to rat E2 in the capacity for binding the E1 component, similar to chicken E2. Thus, it appears that non-mammalian BCKADH E2 is distinct from that in mammals in the structure of interdomain segments, resulting in reduction of overall activity of the enzyme complex.
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Affiliation(s)
- Masatoshi Hakozaki
- Department of Biochemistry, Fukushima Medical University, School of Medicine, 1 Hikarigaoka, Fukushima 960-1295, Japan
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Korotchkina LG, Patel MS. Probing the mechanism of inactivation of human pyruvate dehydrogenase by phosphorylation of three sites. J Biol Chem 2001; 276:5731-8. [PMID: 11092882 DOI: 10.1074/jbc.m007558200] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Activity of the mammalian pyruvate dehydrogenase complex (PDC) is regulated by phosphorylation-dephosphorylation of three serine residues (designated site 1, Ser-264; site 2, Ser-271; site 3, Ser-203) in the alpha subunit of the pyruvate dehydrogenase (E1) component. Substitutions of the phosphorylation sites were generated by site-directed mutagenesis. Glutamate (S1E) and aspartate (S1D) substitutions at site 1 resulted in the complete loss of PDC activity; however, these mutants were variably active in the decarboxylation and 2,6-dichlorophenolindophenol assays. S1Q had only 3% of wild-type PDC activity. The apparent K(m) values for pyruvate increased for the mutants of site 1 when determined in the 2,6-dichlorophenolindophenol assay. The substitutions at sites 2 and 3 caused only moderate reductions in activity in the three assays. S3E had a 27-fold increase in the apparent K(m) for thiamine pyrophosphate and 8-fold increase in the K(i) for pyrophosphate. Site 3 was almost completely protected from phosphorylation by thiamine pyrophosphate. The results show that the size rather than negative charge of the substituted amino acid residue affects the active site of E1 and that modification of each of the three serine residues affect the active site in a site-specific manner for its ability to bind the cofactor and substrates.
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Affiliation(s)
- L G Korotchkina
- Department of Biochemistry, School of Medicine and Biomedical Sciences, State University of New York, Buffalo, New York 14214, USA
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Yang D, Song J, Wagenknecht T, Roche TE. Assembly and full functionality of recombinantly expressed dihydrolipoyl acetyltransferase component of the human pyruvate dehydrogenase complex. J Biol Chem 1997; 272:6361-9. [PMID: 9045657 DOI: 10.1074/jbc.272.10.6361] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The dihydrolipoyl acetyltransferase (E2) component of mammalian pyruvate dehydrogenase complex (PDC) consists of 60 COOH-terminal domains as an inner assemblage and sequentially via linker regions an exterior pyruvate dehydrogenase (E1) binding domain and two lipoyl domains. Mature human E2, expressed in a protease-deficient Escherichia coli strain at 27 degrees , was prepared in a highly purified form. Purified E2 had a high acetyltransferase activity, was well lipoylated based on its acetylation, and bound a large complement of bovine E1. Electron micrographs demonstrated that the inner core was assembled in the expected pentagonal dodecahedron shape with E1 binding around the inner core periphery. With saturating E1 and excess dihydrolipoyl dehydrogenase (E3) but no E3-binding protein (E3BP), the recombinant E2 supported the overall PDC reaction at 4% of the rate of bovine E2.E3BP subcomplex. The lipoates of assembled human E2 or its free bilipoyl domain region were reduced by E3 at rates proportional to the lipoyl domain concentration, but those of the E2.E3BP were rapidly used in a concentration-independent manner consistent with bound E3 rapidly using a set of lipoyl domains localized nearby. Given this restriction and the need for E3BP for high PDC activity, directed channeling of reducing equivalents to bound E3 must be very efficient in the complex. The recombinant E2 oligomer increased E1 kinase activity by up to 4-fold and, in a Ca2+-dependent process, increased phospho-E1 phosphatase activity more than 15-fold. Thus the E2 assemblage fully provides the molecular intervention whereby a single E2-bound kinase or phosphatase molecule rapidly phosphorylate or dephosphorylate, respectively, many E2-bound E1. Thus, we prepared properly assembled, fully functional human E2 that mediated enhanced regulatory enzyme activities but, lacking E3BP, supported low PDC activity.
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Affiliation(s)
- D Yang
- Department of Biochemistry, Kansas State University, Manhattan, Kansas 66506, USA
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5
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Behal R, DeBuysere M, Demeler B, Hansen J, Olson M. Pyruvate dehydrogenase multienzyme complex. Characterization of assembly intermediates by sedimentation velocity analysis. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(18)31703-4] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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6
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Partial activation of the pyruvate dehydrogenase kinase by the lipoyl domain region of E2 and interchange of the kinase between lipoyl domain regions. J Biol Chem 1993. [DOI: 10.1016/s0021-9258(19)74291-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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Wagenknecht T, Grassucci R, Radke G, Roche T. Cryoelectron microscopy of mammalian pyruvate dehydrogenase complex. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(18)54279-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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9
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Perham RN. Domains, motifs, and linkers in 2-oxo acid dehydrogenase multienzyme complexes: a paradigm in the design of a multifunctional protein. Biochemistry 1991; 30:8501-12. [PMID: 1888719 DOI: 10.1021/bi00099a001] [Citation(s) in RCA: 314] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- R N Perham
- Cambridge Centre for Molecular Recognition, Department of Biochemistry, University of Cambridge, England
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Lawson JE, Behal RH, Reed LJ. Disruption and mutagenesis of the Saccharomyces cerevisiae PDX1 gene encoding the protein X component of the pyruvate dehydrogenase complex. Biochemistry 1991; 30:2834-9. [PMID: 2007123 DOI: 10.1021/bi00225a015] [Citation(s) in RCA: 61] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Disruption of the PDX1 gene encoding the protein X component of the mitochondrial pyruvate dehydrogenase (PDH) complex in Saccharomyces cerevisiae did not affect viability of the cells. However, extracts of mitochondria from the mutant, in contrast to extracts of wild-type mitochondria, did not catalyze a CoA- and NAD(+)-linked oxidation of pyruvate. The PDH complex isolated from the mutant cells contained pyruvate dehydrogenase (E1 alpha + E1 beta) and dihydrolipoamide acetyltransferase (E2) but lacked protein X and dihydrolipoamide dehydrogenase (E3). Mutant cells transformed with the gene for protein X on a unit-copy plasmid produced a PDH complex that contained protein X and E3, as well as E1 alpha, E1 beta, and E2, and exhibited overall activity similar to that of the wild-type PDH complex. These observations indicate that protein X is not involved in assembly of the E2 core nor is it an integral part of the E2 core. Rather, protein X apparently plays a structural role in the PDH complex; i.e., it binds and positions E3 to the E2 core, and this specific binding is essential for a functional PDH complex. Additional evidence for this conclusion was obtained with deletion mutations. Deletion of most of the lipoyl domain (residues 6-80) of protein X had little effect on the overall activity of the PDH complex. This observation indicates that the lipoyl domain, and its covalently bound lipoyl moiety, is not essential for protein X function. However, deletion of the putative subunit binding domain (residues approximately 144-180) of protein X resulted in loss of high-affinity binding of E3 and concomitant loss of overall activity of the PDH complex.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- J E Lawson
- Clayton Foundation Biochemical Institute, University of Texas, Austin 78712
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11
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Changes in the core of the mammalian-pyruvate dehydrogenase complex upon selective removal of the lipoyl domain from the transacetylase component but not from the protein X component. J Biol Chem 1990. [DOI: 10.1016/s0021-9258(18)77332-8] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Ozel M, Höglund S, Gelderblom HR, Morein B. Quaternary structure of the immunostimulating complex (iscom). JOURNAL OF ULTRASTRUCTURE AND MOLECULAR STRUCTURE RESEARCH 1989; 102:240-8. [PMID: 2634709 DOI: 10.1016/0889-1605(89)90018-9] [Citation(s) in RCA: 68] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Proteins of either HIV-1, hepatitis B, or rabies virus were incorporated with the adjuvant substance Quil A and cholesterol into the immunostimulating complex: iscom. Formation and symmetry of this regular complex were analyzed by electron microscopy. Micellar structures with a diameter of about 12 nm, occasionally with a 7-nm stain-filled center, were formed in a 0.03% water suspension of Quil A. Cavities or holes appeared in the smooth structures of cholesterol upon the addition of Quil A, and after mixing Quil A and cholesterol 1:1 fragile and flattened structures of matrix were produced with a diameter of about 40 nm. By freeze-drying the matrix was preserved as a cage-like, isometric particle. Stable iscom particles composed of Quil A, cholesterol, and selected viral proteins had an approximate diameter of 32 nm. The particles had an uniform, cage-like structure, exhibiting icosahedral symmetry, irrespective of the viral proteins incorporated. Tilting experiments and rotational image analysis indicated that the iscoms were composed of 20 morphological subunits assembled in a pentagonal dodecahedron with a hole on each of the 12 pentagonal faces. The symmetrical shape of the iscom might explain both its remarkable stability and its capacity to efficiently present antigens to the immune system.
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Affiliation(s)
- M Ozel
- Robert Koch-Institute of the Federal Health Office, Berlin, Federal Republic of Germany
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Gopalakrishnan S, Rahmatullah M, Radke GA, Powers-Greenwood S, Roche TE. Role of protein X in the function of the mammalian pyruvate dehydrogenase complex. Biochem Biophys Res Commun 1989; 160:715-21. [PMID: 2719694 DOI: 10.1016/0006-291x(89)92492-3] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Two lipoyl-bearing subunits--the dihydrolipoyl transacetylase and protein X--form the core of the mammalian pyruvate dehydrogenase complex. Selective removal of the lipoyl domain of protein X results in loss in the activity of the complex with a relationship suggesting the involvement of the lipoyl domain of protein X in a key but not rate limiting step. The dihydrolipoyl dehydrogenase component markedly reduces both the cleavage of protein X and the loss in activity. Using a microplate binding assay, we demonstrate that the lipoyl domain of protein X and the transacetylase component contribute to the binding of the dihydrolipoyl dehydrogenase component. These roles of protein X in the catalytic function and organization of the complex require new reactions and afford an explanation for the unusual stoichiometry of dihydrolipoyl dehydrogenase dimers in the complex.
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Affiliation(s)
- S Gopalakrishnan
- Department of Biochemistry, Kansas State University, Manhattan 66506
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16
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Rahmatullah M, Gopalakrishnan S, Andrews PC, Chang CL, Radke GA, Roche TE. Subunit Associations in the Mammalian Pyruvate Dehydrogenase Complex. J Biol Chem 1989. [DOI: 10.1016/s0021-9258(18)94165-7] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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Carothers DJ, Pons G, Patel MS. Dihydrolipoamide dehydrogenase: functional similarities and divergent evolution of the pyridine nucleotide-disulfide oxidoreductases. Arch Biochem Biophys 1989; 268:409-25. [PMID: 2643922 DOI: 10.1016/0003-9861(89)90309-3] [Citation(s) in RCA: 108] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Dihydrolipoamide dehydrogenase (E3) is the common component of the three alpha-ketoacid dehydrogenase complexes oxidizing pyruvate, alpha-ketoglutarate, and the branched-chain alpha-ketoacids. E3 also participates in the glycine cleavage system. E3 belongs to the enzyme family called pyridine nucleotide-disulfide oxidoreductases, catalyzing the electron transfer between pyridine nucleotides and disulfide compounds. This review summarizes the information available for E3 from a variety of species, from a halophilic archaebacterium which has E3 but no alpha-ketoacid dehydrogenase complexes, to mammalian species. Evidence is reviewed for the existence of two E3 isozymes (one for pyruvate dehydrogenase complex and alpha-ketoglutarate dehydrogenase complex and the other for branched-chain alpha-ketoacid dehydrogenase complex) in Pseudomonas species and for possible mammalian isozymes of E3, one associated with the three alpha-ketoacid dehydrogenase complexes and one for the glycine cleavage system. The comparison of the complete amino acid sequences of E3 from Escherichia coli, yeast, pig, and human shows considerable homologies of certain amino acid residues or short stretches of sequences, especially in the specific catalytic and structural domains. Similar homology is found with the limited available amino acid sequence information on E3 from several other species. Sequence comparison is also presented for other member flavoproteins [e.g., glutathione reductase and mercury(II) reductase] of the pyridine nucleotide-disulfide oxidoreductase family. Based on the known tertiary structure of human glutathione reductase it may be possible to predict the domain structures of E3. Additionally, the sequence information may help to better understand a divergent evolutionary relationship among these flavoproteins in different species.
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Affiliation(s)
- D J Carothers
- Department of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106
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18
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Rahmatullah M, Roche TE. Component requirements for NADH inhibition and spermine stimulation of pyruvate dehydrogenaseb phosphatase activity. J Biol Chem 1988. [DOI: 10.1016/s0021-9258(18)68448-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Pettit FH, Reed LJ. Branched-chain alpha-keto acid dehydrogenase complex from bovine kidney. Methods Enzymol 1988; 166:309-12. [PMID: 3241565 DOI: 10.1016/s0076-6879(88)66042-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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20
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Chapter 13 Measurement of Equilibrium Constants by Exclusion Methods. ACTA ACUST UNITED AC 1988. [DOI: 10.1016/s0301-4770(08)60717-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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21
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Reed LJ, Yeaman SJ. 3 Pyruvate Dehydrogenase. ACTA ACUST UNITED AC 1987. [DOI: 10.1016/s1874-6047(08)60254-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/30/2023]
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Rahmatullah M, Jilka JM, Radke GA, Roche TE. Properties of the pyruvate dehydrogenase kinase bound to and separated from the dihydrolipoyl transacetylase-protein X subcomplex and evidence for binding of the kinase to protein X. J Biol Chem 1986. [DOI: 10.1016/s0021-9258(19)84592-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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23
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Cook KG, Bradford AP, Yeaman SJ. Resolution and reconstitution of bovine kidney branched-chain 2-oxo acid dehydrogenase complex. Biochem J 1985; 225:731-5. [PMID: 3977856 PMCID: PMC1144650 DOI: 10.1042/bj2250731] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Branched-chain 2-oxo acid dehydrogenase complex was resolved into component E1 and E2-kinase subcomplex by gel filtration in the presence of 1 M-NaC1. Essentially all the original activity of the complex can be regained after reconstitution of the component enzymes, reassociation being a rapid process. The specific activities of E1 and E2 were 25.1 and 19.0 units/mg respectively. Non-phosphorylated active E1 has an approx. 6-fold higher affinity for E2 than does phosphorylated E1. The components of the branched-chain 2-oxo acid dehydrogenase complex do not crossreact with the respective components from the pyruvate dehydrogenase complex. The significance of these results and of the tight association of the kinase with E2 are discussed.
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Reed LJ, Damuni Z, Merryfield ML. Regulation of mammalian pyruvate and branched-chain alpha-keto acid dehydrogenase complexes by phosphorylation-dephosphorylation. CURRENT TOPICS IN CELLULAR REGULATION 1985; 27:41-9. [PMID: 3004826 DOI: 10.1016/b978-0-12-152827-0.50011-6] [Citation(s) in RCA: 105] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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