TY - JOUR
T1 - Biliverdin-copper complex at physiological pH
AU - Dimitrijević, Milena S.
AU - Bogdanović Pristov, Jelena
AU - Žižić, Milan
AU - Stanković, Dalibor M.
AU - Bajuk-Bogdanović, Danica
AU - Stanić, Marina
AU - Spasić, Snežana
AU - Hagen, Wilfred
AU - Spasojević, Ivan
N1 - Accepted Author Manuscript
PY - 2019
Y1 - 2019
N2 -
Biliverdin (BV), a product of heme catabolism, is known to interact with transition metals, but the details of such interactions under physiological conditions are scarce. Herein, we examined coordinate/redox interactions of BV with Cu
2+
in phosphate buffer at pH 7.4, using spectrophotometry, HESI-MS, Raman spectroscopy,
1
H NMR, EPR, fluorimetry, and electrochemical methods. BV formed a stable coordination complex with copper in 1:1 stoichiometry. The structure of BV was more planar and energetically stable in the complex. The complex showed strong paramagnetic effects that were attributed to an unpaired delocalized e
-
. The delocalized electron may come from BV or Cu
2+
, so the complex is formally composed either of BV radical cation and Cu
1+
or of BV radical anion and Cu
3+
. The complex underwent oxidation only in the presence of both O
2
and an excess of Cu
2+
, or a strong oxidizing agent, and it was resistant to reducing agents. The biological effects of the stable BV metallocomplex containing a delocalized unpaired electron should be further examined, and may provide an answer to the long-standing question of high energy investment in the catabolism of BV, which represents a relatively harmless molecule per se.
AB -
Biliverdin (BV), a product of heme catabolism, is known to interact with transition metals, but the details of such interactions under physiological conditions are scarce. Herein, we examined coordinate/redox interactions of BV with Cu
2+
in phosphate buffer at pH 7.4, using spectrophotometry, HESI-MS, Raman spectroscopy,
1
H NMR, EPR, fluorimetry, and electrochemical methods. BV formed a stable coordination complex with copper in 1:1 stoichiometry. The structure of BV was more planar and energetically stable in the complex. The complex showed strong paramagnetic effects that were attributed to an unpaired delocalized e
-
. The delocalized electron may come from BV or Cu
2+
, so the complex is formally composed either of BV radical cation and Cu
1+
or of BV radical anion and Cu
3+
. The complex underwent oxidation only in the presence of both O
2
and an excess of Cu
2+
, or a strong oxidizing agent, and it was resistant to reducing agents. The biological effects of the stable BV metallocomplex containing a delocalized unpaired electron should be further examined, and may provide an answer to the long-standing question of high energy investment in the catabolism of BV, which represents a relatively harmless molecule per se.
UR - http://www.scopus.com/inward/record.url?scp=85065545631&partnerID=8YFLogxK
U2 - 10.1039/c8dt04724c
DO - 10.1039/c8dt04724c
M3 - Article
C2 - 30734795
SN - 1477-9226
VL - 48
SP - 6061
EP - 6070
JO - Dalton Transactions
JF - Dalton Transactions
IS - 18
ER -