Enzymatic Deconstruction of Backbone Structures of the Ramified Regions in Pectins

Authors: Wong, Dominic

Submitted to: Protein Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/25/2007
Publication Date: 9/1/2007
Citation: Wong, D. 2007. Enzymatic Deconstruction of Backbone Structures of the Ramified Regions in Pectins. Protein Journal. 27(1):30-42.

Interpretive Summary: Biodegradation of plant cell wall involves a collection of numerous biochemical reactions that are mediated by various complex systems of enzymes. Pectic enzymes degrading polysaccharides are used in fruit juice processing for improved pressing and clarification, and in the pulp and paper industry for enzymatic debarking. The enzymes are useful for the potential development of bioactive compound, and enhancement of biomass degradation in the conversion to biofuel and value-added chemicals. The technological role of a specific enzyme in an application depends on the understanding of the nature of its substrates as well as its structure and action at the molecular level. This manuscript is to review the current knowledge on the occurrence, properties, structures, functions, mechanisms, interactions, and applications of pectic enzymes for the degradation of the highly complex "hairy" region of pectin. A better understanding of these enzymes may provide important insight in their utilization for high efficiency bioconversion of plant biomass to value-added chemicals.

Technical Abstract: The pectic enzymes are a diverse group of enzymes that collectively degrade pectin, a mixture of highly heterogeneous and branched polysaccharides rich in D-galacturonic forming one of the major component of primary cell walls of plants. This review covers the biochemistry of currently known set of enzymes that functions to deconstruct the "ramified region" of pectin. The enzyme group includes hydrolases and lyases that degrade complex domains consisting of rhamnogalacturonans, xylogalacturonans, and other heterogeneous polymers. The chemistry of the enzyme substrates, the biochemical properties of the enzymes, the mechanism of the enzyme actions, and related structures and functions at the molecular level, are described in detail. Applications of these enzymes in fruit juice processing and in the production of bioactive compounds, as well as their technological relevance to the deconstruction of plant cell wall structures for biomass conversion are presented.