Characterization of a carbon monoxide complex of reduced dopamine beta-hydroxylase. Evidence for inequivalence of the Cu(I) centers

Ascorbate-reduced dopamine beta-hydroxylase (DBH) is inhibited by CO in a competitive manner with respect to molecular O2. Measurement of the stoichiometry of CO binding indicates 0.50 CO bound per Cu(I), which provides the first evidence that the Cu(I) centers in the reduced enzyme are structurally...

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Bibliographic Details
Published in:The Journal of biological chemistry 1990-09, Vol.265 (26), p.15383-15386
Main Authors: Blackburn, N J, Pettingill, T M, Seagraves, K S, Shigeta, R T
Format: Article
Language:English
Subjects:
Binding Sites
carbon monoxide
Carbon Monoxide - metabolism
Carbon Monoxide - pharmacology
Copper - metabolism
Dopamine beta-Hydroxylase - antagonists & inhibitors
Dopamine beta-Hydroxylase - metabolism
Kinetics
Protein Binding
Spectrophotometry, Infrared
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Summary:Ascorbate-reduced dopamine beta-hydroxylase (DBH) is inhibited by CO in a competitive manner with respect to molecular O2. Measurement of the stoichiometry of CO binding indicates 0.50 CO bound per Cu(I), which provides the first evidence that the Cu(I) centers in the reduced enzyme are structurally inequivalent. FTIR spectroscopy has been used to detect an infrared absorption band characteristic of coordinated CO, with v(CO) = 2089 cm-1. Comparison of this frequency with those of other Cu(I)-carbonyls in both inorganic and protein systems suggests a coordination site with fewer or less basic ligands than the 3-histidine site of carbon-monoxy hemocyanin.
ISSN:0021-9258
1083-351X
DOI:10.1016/S0021-9258(18)55407-7