Identification and partial purification of an oxidase from lignifying xylem of Leyland cypress (X Cupressocyparis leylandii) |
| |
Authors: | Andrew Richardson G J McDougall |
| |
Institution: | (1) Unit of Plant Biochemistry, Cell and Environmental Physiology Department, Scottish Crop Research Institute, Invergowrie, Dundee, DD2 5DA, UK Fax: (+44) 1382 562426; email:gmcdou@scri.sari.ac.uk, GB |
| |
Abstract: | Oxidase activity was exclusively present in lignifying cells of developing xylem of Leyland cypress. The oxidase was enriched
in 200 mM CaCl2 extracts of crude cell walls and seems to be ionically associated with the cell walls. Oxidase activity was selected and
concentrated using affinity chromatography on Concanavalin-A Sepharose which suggests that it is a high-mannose type glycoprotein.
A subsequent purification step using gel permeation chromatography on Sephadex GF-150 partially separated the oxidase activity
from peroxidase activity. An oxidase band of apparent Mr 92 kD capable of oxidising N, N, N′, N′ - tetramethyl phenylene diamine/α-naphthol was identified after non-denaturing sodium
dodecyl sulphate polyacrylamide gel electrophoresis. The 92 kD oxidase band was enriched in the oxidase-rich fraction and
absent from the peroxidase-rich fraction from the gel permeation step. In addition, the 92 kD oxidase band could be differentiated
from peroxidase bands because it was not intensified by the addition of hydrogen peroxide. The partially purified oxidase
effectively oxidised and polymerised coniferyl alcohol to form insoluble material that yielded a Fourier transform infra-red
spectrum similar to dehydrogenation polymers of coniferyl alcohol. This coniferyl alcohol oxidase appears to be specific to
lignifying xylem cells and may participate in lignin deposition but further studies are required to fully define this oxidase
and its possible homology with other oxidases identified in the lignifying xylem of different species of trees.
Received: 20 May 1997 / Accepted: 7 August 1997 |
| |
Keywords: | Leyland cypress Xylem Lignification Ο xidase Coniferyl alcohol |
本文献已被 SpringerLink 等数据库收录! |
|