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A reappraisal of the mechanism of the photoenzyme protochlorophyllide reductase based on studies with the heterologously expressed protein
Author(s) -
Townley Helen E,
Griffiths W.Trevor,
Nugent Jonathan P
Publication year - 1998
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/s0014-5793(97)01589-5
Subject(s) - protochlorophyllide , reductase , biochemistry , chemistry , escherichia coli , enzyme , photoexcitation , mechanism (biology) , catalysis , enzyme catalysis , oxidoreductase , gene , excited state , physics , philosophy , epistemology , nuclear physics
It is widely believed that protochlorophyllide reductase is a flavoenzyme effecting catalysis by a radical mechanism. Here the cyanobacterial reductase has been isolated from Escherichia coli overexpressing the Synechocystis gene. The purified enzyme, while retaining full activity, has no detectable flavine. No radical derived ESR signal was observed during catalysis or on photoexcitation under non‐catalytic conditions. Mechanistic implications of the findings are discussed.