EXTRACELLULAR LACCASES AND PEROXIDASES FROM SYCAMORE MAPLE (ACER-PSEUDOPLATANUS) CELL-SUSPENSION CULTURES - REACTIONS WITH MONOLIGNOLS AND LIGNIN MODEL COMPOUNDS

Citation
R. Sterjiades et al., EXTRACELLULAR LACCASES AND PEROXIDASES FROM SYCAMORE MAPLE (ACER-PSEUDOPLATANUS) CELL-SUSPENSION CULTURES - REACTIONS WITH MONOLIGNOLS AND LIGNIN MODEL COMPOUNDS, Planta, 190(1), 1993, pp. 75-87
Citations number
51
Journal title
PlantaACNP
ISSN journal
00320935
Volume
190
Issue
1
Year of publication
1993
Pages
75 - 87
Database
ISI
SICI code
0032-0935(1993)190:1<75:ELAPFS>2.0.ZU;2-E
Abstract
We have investigated the abilities of extracellular enzymes from dark- grown cell-suspension cultures of sycamore maple (Acer pseudoplatanus L.) to oxidize monolignols, the precursors for lignin biosynthesis in plants, as well as a variety of other lignin-related compounds. Laccas e and peroxidase both exist as a multiplicity of isoenzymes in filtrat es of spent culture medium, but their abilities to produce water-insol uble, dehydrogenation polymers (DHPs) from the monolignols (in the pre sence of hydrogen peroxide for the peroxidase reaction) appear identic al whether or not the enzymes are purified from the concentrated filtr ates or left in a crude mixture. The patterns of bonds formed in these DHPs are identical to those found in DHPs synthesized using horseradi sh peroxidase or fungal laccase, and many of these bonds are found in the natural lignins extracted from different plant sources. On the oth er hand, sycamore maple laccase is very much less active on phenolic s ubstrates containing multiple aromatic rings than is sycamore maple pe roxidase. We suggst that whereas laccase may function during the early stages of lignification to polymerize monolignols into oligo-lignols, cell-wall peroxidases may function when H2O2 is produced during the l ater stages of xylem cell development or in response to environmental stresses.