N. Rothschild et al., LIGNIN PEROXIDASE ISOZYMES FROM PHANEROCHAETE-CHRYSOSPORIUM CAN BE ENZYMATICALLY DEPHOSPHORYLATED, Applied and environmental microbiology, 63(3), 1997, pp. 857-861
The extracellular lignin peroxidase (LIP) protein profile of the fungu
s Phanerochaete chrysosporium, grown in nonimmersed liquid culture und
er conditions of excess nitrogen, changed markedly with culture age, A
t peak LIP activity (day 4), the heme-protein profile in the extracell
ular fluid, analyzed by anion-exchange high-pressure liquid chromatogr
aphy, was characterized by a predominance of the LIP isozymes H1 and H
2, small amounts of H6 and H8, and other minor peaks, designated Ha an
d Hb. On day 5, the level of H1 increased and it became the dominant i
sozyme, with a corresponding decrease in the level of H2, Moreover, th
e relative levels of H6 and H8 decreased with corresponding increases
in Ha and Hb levels, This change in LIP profile occurred extracellular
ly and resulted from the enzymatic dephosphorylation of LIP isozymes,
An enzymatic fraction responsible for LIP isozyme dephosphorylation, t
ermed LIP dephosphorylating (LpD) fraction, was partially purified fro
m the culture fluid, Incubation of the LpD fraction with P-32-labeled
H2, H6, H8, and H10 isozymes separated from nitrogen-limited cultures
resulted in the formation of the dephosphorylated isozymes H1, Ha, Hb,
and Hc, respectively, Dephosphorylation did not significantly change
the catalytic properties of the LIP isozymes with veratryl alcohol as
a substrate, LIP dephosphorylation is therefore suggested to be a post
translational modification process catalyzed extracellularly by the Lp
D activity.