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Identification of the ligand trans to thiolate in cytochrome P‐450 LM2 by chemical modification
Author(s) -
Jänig G.-R.,
Dettmer R.,
Usanov S.A.,
Ruckpaul K.
Publication year - 1983
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(83)80416-5
Subject(s) - tetranitromethane , chemistry , nitration , heme , tyrosine , cytochrome , chemical modification , stereochemistry , ligand (biochemistry) , hemeprotein , porphyrin , residue (chemistry) , cytochrome p450 , enzyme , biochemistry , receptor , organic chemistry
About 3 tyrosine residues of cytochrome P‐450 LM2 are accessible to chemical modification with tetranitromethane. Nitration of two tyrosines inactivates the enzyme to about 20%. The partial formation of a hyper‐porphyrin spectrum originating from the pK shift by nitration and formation of a tyrosinate is prevented by modification in the presence of the inhibitor metyrapone. These findings support the assumption of a tyrosine residue as sixth ligand of the heme iron in cytochrome P‐450 LM2.