Replacement of unlabeled γ-butyrobetaine with γ-[2,3,4-2H6]butyrobetaine has a profound effect on the stoichiometry between decarboxylation of 2-oxoglutarate and hydroxylation in the reaction catalyzed by human γ -butyrobetaine hydroxylase. The ratios between decarboxylation and hydroxylation are 1.16 with Unlabeled and 7.48 with deuterated γ-butyrobetaine as substrate. From these ratios an internal isotope effect of 41 has been calculated. DV in the overall reaction measured as 2- oxoglutarate decarboxylation is 2.5 and DV/K is 1.0. For γ-butyrobetaine hydroxylase from Pseudomonas sp. AK 1, 2-oxoglutarate decarboxylation exceeds hydroxylation with 10% when deuterated γ-butyrobetaine is used. No excess was found with unlabeled substrate and no internal isotope effect could be calculated. DV for the bacterial enzyme is 6.
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Research Article|
May 01 1984
Uncoupling and isotope effects in γ-butyrobetaine hydroxylation
Elisabeth Holme;
Elisabeth Holme
1Department of Clinical Chemistry, University of Gothenburg, Sahlgren's Hospital, S-413 45 Gothenburg, Sweden
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Sven Lindstedt;
Sven Lindstedt
1Department of Clinical Chemistry, University of Gothenburg, Sahlgren's Hospital, S-413 45 Gothenburg, Sweden
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Ingalill Nordin
Ingalill Nordin
1Department of Clinical Chemistry, University of Gothenburg, Sahlgren's Hospital, S-413 45 Gothenburg, Sweden
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Publisher: Portland Press Ltd
Received:
April 19 1984
Online ISSN: 1573-4935
Print ISSN: 0144-8463
© 1984 The Biochemical Society
1984
Biosci Rep (1984) 4 (5): 433–440.
Article history
Received:
April 19 1984
Citation
Elisabeth Holme, Sven Lindstedt, Ingalill Nordin; Uncoupling and isotope effects in γ-butyrobetaine hydroxylation. Biosci Rep 1 May 1984; 4 (5): 433–440. doi: https://doi.org/10.1007/BF01122509
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