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8213332 
Journal Article 
Spectrophotometric investigations with hexa-coordinate ferric lignin peroxidase: Does water retention at the active site influence catalysis? 
Brã¼Ck, TB; Harvey, PJ 
2002 
Yes 
Biochemical and Biophysical Research Communications
ISSN: 0006-291X
EISSN: 1090-2104 
297 
2 
406-411 
English 
Native lignin peroxidase (LIP) can adopt either a stable penta- or hexa-coordinate state. We have examined catalysis with hexa-coordinate ferric LIP as the starting material, using rapid scanning spectrophotometry. Initial two-electron oxidation of hexa-coordinate native LIP by H2O2 (Compound I formation) was accompanied by a shifting isosbestic point (419→416 nm), consistent with displacement of a resident water molecule, prior to the reaction of the ferric iron with H2O2. The Compound I species derived from a hexa-coordinate ferric state shows an unusual peak at 520 nm, which may be due to water retention in the vicinity of the heme active site. Compound I reduction by veratryl alcohol showed saturation kinetics, which contrasts with the situation observed when Compound I is derived from a penta-coordinate ferric state. The data inferred that water can interfere with heme access by electron donors, altering the mechanism of Compound I reduction. © 2002 Elsevier Science (USA). All rights reserved. 
Compound I; Compound II; Ferric LIP; Hexa-coordinate state; Peroxidase; Resident water