Abstract
Lignins are aromatic polymers of methoxylated phenylpropanoids connected by both ether and carbon-carbon linkages, and classified into three major groups, guaiacyl lignin in softwoods (gymnosperms), guaiacyl-syringyl lignin in hardwoods (angiosperms) and guaiacyl-syringyl-p-hydroxyphenyl lignin in grasses (gramineae) on their monomeric units. In grass lignins p-coumaric acid (5∼10%) is ester linked mostly at γ-position of the propyl side chain. Biochemical studies of lignification have elucidated that 1) lignins are formed by dehydrogenative polymerization of monolignols catalyzed by peroxidase and laccase, 2) biosynthesis of monolignols is via shikimate-cinnamate pathway, 3) syringyl lignin in hardwoods is formed from the syringyl monolignol, sinapyl alcohol, derived from 5-hydroxyguaiacyl precursors, and that 4) ferulate 5-hydroxylase, coniferyl aldehyde 5-hydroxylase and probably coniferyl alcohol 5-hydroxylase are involved in the biosynthesis of the syringyl monolignol from guaiacyl monolignol precursors in respective hardwoods.(Communicated by Saburo TAMURA, M. J. A., Oct. 14, 2003)
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
