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Charlesworth MC, McCormick DJ, Madden B, Ryan RJ. Inhibition of human choriotropin binding to receptor by human choriotropin alpha peptides. A comprehensive synthetic approach. J Biol Chem 1987; 262:13409-16. [PMID: 3654620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Synthetic overlapping peptides of the alpha-subunit of human chorionic gonadotropin (hCG) were made by solid-phase peptide synthesis employing a comprehensive synthetic approach. The entire primary structure of the alpha-subunit was synthesized as a series of nine consecutive peptides, each 15 residues in length, and overlapping with its two adjacent neighbors by 5 residues on each side. Receptor binding activity of each synthetic peptide was measured by the inhibition of binding of 125I-labeled hCG to rat ovarian receptor. Peptides alpha 21-35, alpha 31-45, alpha 71-85, and alpha 81-92 were shown to compete for binding with native hCG, thus demonstrating that at least two regions on the alpha-subunit may be part of the binding site(s) of the hormone. The low affinity of the peptides (10(-5)-10(-6) M) compared to native hormone (10(-10) M) for receptor is not unexpected due to the probability of discontinuous and multiple sites involved in receptor binding. An ultrapure preparation of hCG alpha-subunit also had low affinity (10(-5), suggesting that conformational changes upon combination with beta-subunit to form dimer or changes in conformation after binding are necessary for high affinity interaction. These results correlate with previous predictions of binding sites based on studies employing chemical and enzymatic modifications of intact hormone and show that synthetic peptide strategies are helpful in the elucidation of protein structure and function.
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102
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Moore JT, Hagstrom J, McCormick DJ, Harvey S, Madden B, Holicky E, Stanford DR, Wieben ED. The major clotting protein from guinea pig seminal vesicle contains eight repeats of a 24-amino acid domain. Proc Natl Acad Sci U S A 1987; 84:6712-4. [PMID: 3477802 PMCID: PMC299153 DOI: 10.1073/pnas.84.19.6712] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The complete amino acid sequence of the major clotting protein from the guinea pig seminal vesicle (SVP-1) has been determined by nucleotide sequencing of cDNA clones corresponding to the 3' terminus of an mRNA that codes for a protein precursor to SVP-1. The first 40 amino acids of the derived protein sequence are identical to those determined by N-terminal sequencing of SVP-1 isolated from the lumen of the seminal vesicle. This finding confirms that SVP-1 is cleaved from the C terminus of a larger precursor protein. The portion of the nucleotide sequence that codes for SVP-1 contains eight highly homologous but imperfect repeats of a 72-nucleotide domain. This repeated structure is also evident at the amino acid level. The consensus 24-amino acid repeat unit contains two lysine and three glutamine residues. Since the clotting of SVP-1 is known to involve the formation of gamma-glutamyl-epsilon-lysine crosslinks, it is likely that the 24-amino acid repeating unit is the unit of function of SVP-1.
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103
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Charlesworth MC, McCormick DJ, Madden B, Ryan RJ. Inhibition of human choriotropin binding to receptor by human choriotropin alpha peptides. A comprehensive synthetic approach. J Biol Chem 1987. [DOI: 10.1016/s0021-9258(19)76441-2] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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104
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Lennon VA, Griesmann GA, McCormick DJ, Huang ZX, Feng H, Lambert EH. Definition of myasthenogenic sites of the human acetylcholine receptor using synthetic peptides. Ann N Y Acad Sci 1987; 505:439-50. [PMID: 2446556 DOI: 10.1111/j.1749-6632.1987.tb51314.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Experimental autoimmune myasthenia gravis (EAMG) and antibodies that modulate AChRs from cultured human muscle are induced by a disulfide-looped peptide comprising the human acetylcholine receptor (AChR) alpha-subunit residues 125-147 (H alpha 125-147). To delineate the essential antigenic requirements for induction of EAMG by this peptide, a series of peptides was synthesized: (a) a nonlooped analog (Cys 128 replaced by Ser) stimulated modulating autoantibodies, induced EAMG, and bound antibodies induced by native AChR; (b) H alpha 131-147, a heptadecylpeptide shorter by 6 N-terminal residues, induced modulating antibodies, EAMG, and T cells that responded to H alpha 125-147, but not to H alpha 137-147; (c) H alpha 137-147, an undecapeptide shorter than H alpha 125-147 by 12 N-terminal residues, did not stimulate T cells or induce antibody production, but it bound antibodies generated by the longer peptides. Thus, when coupled to an epitope that could stimulate helper T cells, the region 137-147 was able to stimulate B cells. This study has defined a myasthenogenic region of the human AChR's alpha-subunit, 17 amino acids long, that contains several distinct epitopes, including at least one N-terminal site inducing T-cell responses (region 131-136) and two possibly overlapping sites that induce antibodies (regions 131-136 and 137-147). Further definition of antigenic sites inducing helper and suppressor T-cell responses and stimulating production of autoantibodies to AChR is essential to the goal of antigen-specific immunotherapy for myasthenia gravis.
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105
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McCormick DJ, Shuck JW, Ansinelli RA. Intermittent pacemaker syndrome: revision of VVI pacemaker to a new cardiac pacing mode for tachy-brady syndrome. Pacing Clin Electrophysiol 1987; 10:372-7. [PMID: 2437541 DOI: 10.1111/j.1540-8159.1987.tb05975.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
A patient with tachy-brady syndrome manifested by paroxysmal atrial fibrillation and symptomatic sinus bradycardia and treated by VVI pacing developed pacemaker syndrome during episodes of ventricular pacing. His cardiac pacemaker was revised to a dual chamber system utilizing the new AV sequential DDI pacing mode which eliminated pacemaker-related tachycardias and totally abolished the pacemaker syndrome symptoms. There have been no further episodes of atrial fibrillation, possibly due to elimination of temporal dispersion of refractory periods during bradycardia. The propensity for atrial fibrillation has also been minimized by excluding competitive atrial stimulation during DVI pacing. The DDI mode provides the clinician increased utility and flexibility in the use of AV sequential pacing therapy.
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106
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Collins LM, Cliff N, McCormick DJ, Zatkin JL. Factor Recovery in Binary Data Sets: A Simulation. MULTIVARIATE BEHAVIORAL RESEARCH 1986; 21:377-391. [PMID: 26800967 DOI: 10.1207/s15327906mbr2103_6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The present study compares the performance of phi coefficients and tetrachorics along two dimensions of factor recovery in binary data. These dimensions are (a) accuracy of nontrivial factor identification, and (b) factor structure recovery given a priori knowledge of the correct number of factors to rotate. Nontrivial factor identification was poor for both indices, with phi's performing slightly better than tetrachorics. In contrast, factor structure recovery was quite good when the correct number of factors was rotated. Phi coefficients generally yielded better factor structure recovery than tetrachorics and were better at preventing items from intruding onto factors where they did not belong, while tetrachorics were better than phi's at preventing items from being omitted from factors where they should have been included. The solutions based on tetrachorics contained many Heywood cases. It is suggested that for most applications it is preferable to base factor analysis on phi coefficients.
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107
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Lennon VA, McCormick DJ, Lambert EH, Griesmann GE, Atassi MZ. Region of peptide 125-147 of acetylcholine receptor alpha subunit is exposed at neuromuscular junction and induces experimental autoimmune myasthenia gravis, T-cell immunity, and modulating autoantibodies. Proc Natl Acad Sci U S A 1985; 82:8805-9. [PMID: 3878521 PMCID: PMC391526 DOI: 10.1073/pnas.82.24.8805] [Citation(s) in RCA: 82] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
A major antigenic region of native nicotinic acetylcholine receptors (AcChoR) has been identified by using a synthetic disulfide-looped peptide corresponding to alpha-subunit residues 125-147 of Torpedo electric organ AcChoR: Lys-Ser-Tyr-Cys-Glu-Ile-Ile-Val-Thr-His-Phe- Pro-Phe-Asp-Gln-Gln-Asn-Cys-Thr-Met-Lys-Leu-Gly. The peptide bound 26-56% of polyclonal antibodies induced in rat, rabbit, and dog by immunization with native AcChoR. Rats inoculated with 50 micrograms of unconjugated peptide developed helper T-cell responses, delayed hypersensitivity, and antibodies to native AcChoR. Anti-peptide antibodies were more reactive with native than denatured AcChoR and bound to the alpha subunit. Some reacted exclusively with mammalian muscle AcChoR, some induced modulation of AcChoR on cultured myotubes, but none inhibited binding of alpha-bungarotoxin to solubilized or membrane-associated AcChoR. Repeated immunization induced experimental autoimmune myasthenia gravis: clinical signs in one rat and electrophysiologic and/or biochemical signs in 10 of 11 rats. Thus, at least part of the corresponding region of the mammalian AcChoR alpha subunit is extracellular at the neuromuscular junction and a potential target for pathogenic autoantibodies in patients with acquired myasthenia gravis.
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108
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McCormick DJ, Lennon VA, Atassi MZ. Antigenicity of synthetic peptides 159-169 and 151-169 of Torpedo acetylcholine receptor alpha chain. Biochem J 1985; 231:245-6. [PMID: 4062890 PMCID: PMC1152736 DOI: 10.1042/bj2310245b] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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109
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McCormick DJ, Lennon VA, Atassi MZ. Synthesis of an antigenic site of native acetylcholine receptor peptide 159-169 of Torpedo acetylcholine receptor alpha-chain. Biochem J 1985; 226:193-7. [PMID: 2579640 PMCID: PMC1144692 DOI: 10.1042/bj2260193] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
A region of the alpha-subunit of the nicotinic acetylcholine receptor (AChR) of the Torpedo electric organ, containing residues 161-166, has been proposed to be a major antigenic site in the native AChR protein. We report the synthesis of a peptide corresponding to residues 159-169, which contains the proposed antigenic region. In quantitative radiometric titrations, radiolabelled anti-(native AChR) antibodies from three different species, rabbit, rat and dog, exhibited considerable binding (approx. 15% relative to native AChR) to Sepharose-immobilized peptide 159-169, but did not bind significantly to Sepharose-immobilized unrelated proteins or peptides. Specificity was further confirmed by the finding that no rabbit anti-AChR antibodies bound to the peptide after absorption with native AChR. These data indicate that the region 159-169 contains an antigenic site that is readily accessible in solubilized native Torpedo AChR.
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110
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McCormick DJ, Atassi MZ. Localization and synthesis of the acetylcholine-binding site in the alpha-chain of the Torpedo californica acetylcholine receptor. Biochem J 1984; 224:995-1000. [PMID: 6525183 PMCID: PMC1144538 DOI: 10.1042/bj2240995] [Citation(s) in RCA: 82] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The sequence of the alpha-chain of the acetylcholine receptor of T. californica has been determined by recent cloning studies. The integrity of the disulphide bond between Cys-128 and cys-142 has been shown to be important for the maintenance of the binding activity of the receptor, thus implicating the regions around the disulphide bridge in binding with acetylcholine. In the present work, a synthetic peptide containing this loop region (residues 125-147) was synthesized. Solid-phase radiometric binding assays demonstrated a high binding of 125I-labelled alpha-bungarotoxin to the synthetic peptide. It was further shown that the free peptide bound well to [3H]acetylcholine. Additional experiments demonstrated that pretreatment of peptide 125-147 with 2-mercaptoethanol destroyed its binding activity, clearly showing that the integrity of the disulphide structure was essential for binding. Unlabelled acetylcholine also inhibited the binding of labelled acetylcholine to the synthetic peptide. The region 125-147, therefore, contains essential elements of the acetylcholine binding site of the Torpedo receptor.
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111
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Shuck JW, McCormick DJ, Cohen IS, Oetgen WJ, Brinker JA. Percutaneous balloon valvuloplasty of the pulmonary valve: role of right to left shunting through a patent foramen ovale. J Am Coll Cardiol 1984; 4:132-5. [PMID: 6736439 DOI: 10.1016/s0735-1097(84)80330-7] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Percutaneous balloon valvuloplasty was performed on a patient with pulmonary stenosis. Right to left shunting through a patent foramen ovale during balloon inflation was documented by contrast two-dimensional echocardiography. Right and left ventricular pressures recorded during balloon inflation showed a decrease in left ventricular end-diastolic pressure and equilibration with right ventricular end-diastolic pressure. Systemic hypotension was minimal during balloon inflation, possibly due to persistent filling of the left ventricle via the patent foramen ovale. Persistent right ventricular systolic hypertension immediately after valvuloplasty may have been due to infundibular narrowing and resolved on restudy 2 weeks later.
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112
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McCormick DJ, Fredricks WW, Tebo TH, Calvanico NJ. The antigens of pigeon breeder's disease. VII. Isoelectric focusing studies on unfractionated pigeon dropping extract. THE JOURNAL OF IMMUNOLOGY 1982. [DOI: 10.4049/jimmunol.129.4.1493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Abstract
Isoelectric focusing (IEF) studies on pigeon dropping extracts (PDE) revealed that it is a complex mixture of components that are acidic in nature. Chromatographically purified antigens PDEB, PDE1, and PDE3 showed multiple bands in IEF, indicating a microheterogeneity of these components, with peak concentrations focusing at pH 6.1, 4.6, and 3.8, respectively. The isoelectric points are compatible with the chromatographic behavior of these antigens on DEAE-cellulose. Crossed immunoelectrofocusing (CRIF) resolved PDE into seven precipitin lines with rabbit antiserum in a pH gradient from 3.5 to 9.5, and into nine precipitable components in a pH gradient from 2.5 to 7.0. The complexity of this antigen source appears to reside in the heterogeneity of immunologically related antigens. A comparison of pigeon breeder's sera by CRIF of PDE revealed a qualitative difference in precipitation patterns obtained with symptomatic and asymptomatic individuals. Sera from all (eight out of eight) of the symptomatic breeders tested precipitated an unidentified component of PDE, whereas none (zero out of four) of the sera from asymptomatic breeders detected this antigen. These results suggest that CRIF of PDE is useful as a diagnostic tool and that some specific component of PDE may be involved in the pathogenesis of the disease.
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113
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McCormick DJ, Fredricks WW, Tebo TH, Calvanico NJ. The antigens of pigeon breeder's disease. VII. Isoelectric focusing studies on unfractionated pigeon dropping extract. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 1982; 129:1493-8. [PMID: 7108215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Isoelectric focusing (IEF) studies on pigeon dropping extracts (PDE) revealed that it is a complex mixture of components that are acidic in nature. Chromatographically purified antigens PDEB, PDE1, and PDE3 showed multiple bands in IEF, indicating a microheterogeneity of these components, with peak concentrations focusing at pH 6.1, 4.6, and 3.8, respectively. The isoelectric points are compatible with the chromatographic behavior of these antigens on DEAE-cellulose. Crossed immunoelectrofocusing (CRIF) resolved PDE into seven precipitin lines with rabbit antiserum in a pH gradient from 3.5 to 9.5, and into nine precipitable components in a pH gradient from 2.5 to 7.0. The complexity of this antigen source appears to reside in the heterogeneity of immunologically related antigens. A comparison of pigeon breeder's sera by CRIF of PDE revealed a qualitative difference in precipitation patterns obtained with symptomatic and asymptomatic individuals. Sera from all (eight out of eight) of the symptomatic breeders tested precipitated an unidentified component of PDE, whereas none (zero out of four) of the sera from asymptomatic breeders detected this antigen. These results suggest that CRIF of PDE is useful as a diagnostic tool and that some specific component of PDE may be involved in the pathogenesis of the disease.
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Abstract
1. The metabolism of the beta-adrenergic blocking agent practolol has been studied in a variety of small animal species, using both ring- and acetyl-14C-labelled material. After oral dosing at 100 mg/kg, elimination of 14C in urine and expired air was monitored, and urinary metabolite patterns were examined by t.l.c. 2. Marmoset was unusual in extensively deacetylating practolol (c. 57% dose). Urinary elimination was low, with only 25% being recovered in 4 days; over 30% of urinary 14C was present as desacetyl practolol, whereas less than 50% was unchanged practolol. 3. Hamster was also atypical, in its extensive hydroxylation of practolol. Urine contained 60% dose; 11% of urinary radioactivity was present as 3-hydroxypractolol, much of the polar material present (48%) appeared to be a conjugate of this, and only 35% was present as practolol. 4. For the other species studied (rat, mouse, guinea-pig and rabbit, metabolism was more limited. Deacetylation was typically about 5%, but was somewhat higher in the mouse (8--14%). Urine was the major route of elimination and practolol represented 50--90% of urinary radioactivity. 5. Despite extensive toxicity studies, both in species which metabolize practolol similarly to man and in species such as the hamster and marmoset which metabolize practolol extensively, no animal model has been found for the human adverse reactions.
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Abstract
The harvesting and consumption of wild mushrooms has become a popular pastime in many areas of the United States. Reports of mushroom poisonings and fatalities have been increasing since 1964. Between May 1973 and April 1978, 16 cases of mushroom poisoning were treated at our institution, including 13 within a 12-month period ending April 1978. All patients exhibited either gastrointestinal or neurologic symptoms, which responded to supportive therapy. There were no fatalities. In most cases, the clinical course can be predicted and appropriate therapy instituted if the mushroom is identified or if the interval between the ingestion and the onset of symptoms can be ascertained and certain characteristic symptoms are observed.
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116
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McCormick DJ, Broekema VJ. Size estimation, perceptual recognition, and cardiac rate response in acute paranoid and nonparanoid schizophrenics. JOURNAL OF ABNORMAL PSYCHOLOGY 1978. [PMID: 681611 DOI: 10.1037//0021-843x.87.4.385] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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117
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Reeves PR, Case DE, Jepson HT, McCormick DJ, Nicholls JT, Felix RH, Holt PJ, Zacharias FJ, Fluke RW. Practolol metabolism. II. Metabolism in human subjects. J Pharmacol Exp Ther 1978; 205:489-98. [PMID: 641844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
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118
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McCormick DJ, Broekema VJ. Size estimation, perceptual recognition, and cardiac rate response in acute paranoid and nonparanoid schizophrenics. JOURNAL OF ABNORMAL PSYCHOLOGY 1978; 87:385-98. [PMID: 681611 DOI: 10.1037/0021-843x.87.4.385] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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119
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Sramek SJ, Frerman FE, McCormick DJ, Duncombe GR. Substrate-induced conformational changes and half-the-sites reactivity in the Escherichia coli CoA transferase. Arch Biochem Biophys 1977; 181:525-33. [PMID: 332081 DOI: 10.1016/0003-9861(77)90259-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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