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High‐resolution XANES studies on vanadium‐containing haloperoxidase: pH‐dependence and substrate binding
Author(s) -
Küsthardt Ulrich,
Hedman Britt,
Hodgson Keith O.,
Hahn Rainer,
Yilter Hans
Publication year - 1993
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(93)80180-3
Subject(s) - vanadium , xanes , chemistry , bromide , inorganic chemistry , vanadate , x ray absorption spectroscopy , absorption spectroscopy , hydrogen peroxide , substrate (aquarium) , absorption (acoustics) , spectroscopy , materials science , organic chemistry , quantum mechanics , composite material , physics , oceanography , geology
High‐resolution X‐ray absorption vanadium K‐edge spectra were recorded for samples of vanadium‐containing bromoperoxidase from the brown alga, Ascophyllum nodosum , at pH 9, 7, 5 and 4, as well as for enzyme samples containing the substrates, hydrogen peroxide and bromide. The well‐resolved features of the XANES spectra are discussed. The pH‐dependence of the structure of the active site has been studied revealing no significant change of the absorption features. We were able to detect an interaction of H 2 O 2 with the vanadium site of the bromoperoxidase using XAS spectroscopy, whereas addition of bromide causes no energy shift of the XANES spectrum. The possible role of vanadium during the enzymatic reaction is discussed on the basis of our results.