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Volumn 130, Issue 20, 2008, Pages 6577-6585

Experimental evidence for enzyme-enhanced coupled motion/quantum mechanical hydrogen tunneling by ketosteroid isomerase

Author keywords

[No Author keywords available]

Indexed keywords

DEUTERIUM; ELECTRON TRANSPORT PROPERTIES; ENZYMES; ISOMERIZATION; RATE CONSTANTS; REACTION KINETICS;

EID: 43949138259     PISSN: 00027863     EISSN: None     Source Type: Journal    
DOI: 10.1021/ja0732330     Document Type: Article
Times cited : (21)

References (71)
  • 21
    • 43949133450 scopus 로고    scopus 로고
    • Ph.D. Thesis, University of Maryland Baltimore County, Baltimore, MD
    • Houck, W. J. Ph.D. Thesis, University of Maryland Baltimore County, Baltimore, MD, 2004.
    • (2004)
    • Houck, W.J.1
  • 32
    • 43949100034 scopus 로고    scopus 로고
    • We later found this synthetic method to be irreproducible, and we have since developed an easier, more reproducible method of tosylation based on the work of Velusamy et al, Velusamy, S. Kirankunar, J. S. Punniyamurthy, T. Tetrahedron Lett. 2004, 45, 203) In a flask equipped with a Dean-Stark trap, 2.884 g (10 mmol) of 3-β-hydroxy-5-androstene-17-one, 1.90 g (10 mmol) of p-toluenesulfonic acid monohydrate and 119 mg (5 mol, of cobalt hexahydrate in 40 mL of 1,2-dichloroethane were stirred and refluxed for 45 minutes. Solvent was removed under reduced pressure, and the residue was dissolved in ethyl acetate. The organic phase was washed in 1 N HCl, water, sodium bicarbonate, and water. After drying (MgSO4) and filtration, the solvent was removed, and the residue was purified by column chromatography by using silica gel (Merck 60) and hexane:ethyl acetate (1:1, Recrystallization from ethyl acetate-hexane gave 83% yield 3.667 g
    • We later found this synthetic method to be irreproducible, and we have since developed an easier, more reproducible method of tosylation based on the work of Velusamy et al. (Velusamy, S. Kirankunar, J. S. Punniyamurthy, T. Tetrahedron Lett. 2004, 45, 203) In a flask equipped with a Dean-Stark trap, 2.884 g (10 mmol) of 3-β-hydroxy-5-androstene-17-one, 1.90 g (10 mmol) of p-toluenesulfonic acid monohydrate and 119 mg (5 mol%) of cobalt hexahydrate in 40 mL of 1,2-dichloroethane were stirred and refluxed for 45 minutes. Solvent was removed under reduced pressure, and the residue was dissolved in ethyl acetate. The organic phase was washed in 1 N HCl, water, sodium bicarbonate, and water. After drying (MgSO4) and filtration, the solvent was removed, and the residue was purified by column chromatography by using silica gel (Merck 60) and hexane:ethyl acetate (1:1). Recrystallization from ethyl acetate-hexane gave 83% yield (3.667 g).
  • 38
    • 43949127823 scopus 로고    scopus 로고
    • The data were manually edited such that they were evenly weighted according to changes in absorbance. Typically, five absorbance readings per 0.001 AU increase were kept, and the rest of the data was discarded
    • The data were manually edited such that they were evenly weighted according to changes in absorbance. Typically, five absorbance readings per 0.001 AU increase were kept, and the rest of the data was discarded.
  • 39
    • 43949099014 scopus 로고    scopus 로고
    • Ph.D. Thesis, University of Maryland Baltimore County, Baltimore, MD
    • Wilde, T. C. Ph.D. Thesis, University of Maryland Baltimore County, Baltimore, MD, 2005.
    • (2005)
    • Wilde, T.C.1
  • 42
    • 43949102803 scopus 로고    scopus 로고
    • Strictly speaking, these equations are appropriate for analyses when the isotopic molecule is present in trace amounts. Because of the small KIEs measured here, the errors introduced by using these simpler equations are less than 0.5%, which is considerably smaller than the experimental error.
    • Strictly speaking, these equations are appropriate for analyses when the isotopic molecule is present in trace amounts. Because of the small KIEs measured here, the errors introduced by using these simpler equations are less than 0.5%, which is considerably smaller than the experimental error.
  • 53
    • 43949104179 scopus 로고    scopus 로고
    • By assuming that the KIE of the uncatalyzed reaction is within 15% of the observed KIE, the contribution from the uncatalyzed rate is less than 0.5%.
    • By assuming that the KIE of the uncatalyzed reaction is within 15% of the observed KIE, the contribution from the uncatalyzed rate is less than 0.5%.
  • 54
    • 0003612579 scopus 로고
    • Collins, C. J, Bowman, N. S, Eds, Van Nostrand Reinhold: New York
    • Collins, C. J., Bowman, N. S., Eds. Isotope Effects in Chemical Reactions; Van Nostrand Reinhold: New York, 1970.
    • (1970) Isotope Effects in Chemical Reactions
  • 55
    • 0009942589 scopus 로고
    • Cleland, W. W, O'Leary, M. H, Northrop, D. B, Eds, University Park: Baltimore
    • Cleland, W. W., O'Leary, M. H., Northrop, D. B., Eds. Isotope Effects on Enzyme-Catalyzed Reactions; University Park: Baltimore, 1977.
    • (1977) Isotope Effects on Enzyme-Catalyzed Reactions
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    • 0000753204 scopus 로고
    • Am. Chem. Soc
    • Saunders, W. H., Jr J. Am. Chem. Soc. 1994, 116, 5400-5404.
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    • Saunders, W.H.1


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.