Nano Science and Technology Institute
Nanotech 2011 Vol. 3
Nanotech 2011 Vol. 3
Nanotechnology 2011: Bio Sensors, Instruments, Medical, Environment and Energy
 
Chapter 3: Bio Nano Materials
 

Characterization of Nanostructural Modifications Introduced into a Model Pectic Homogalacturonan by Esterases or Chemical Saponification and Modeling of Enzyme Mode of Action

Authors:R.G. Cameron, G.A. Luzio, Y. Kim, P. Vasu, B.J. Savary, M.A.K. Williams
Affilation:United States Department of Agriculture, Agricultural Research Service, US
Pages:275 - 278
Keywords:pectin, homogalacturonan, pectin methylesterase, petinesterase, enzyme
Abstract:Pectin functionality is largely dependent on the ratio of methylesterified/demethylesterified galacturonic acid (GalA) residues present in its polymeric homogalacturonan region (40 – 60 nm in length, 100 – 150 GalA residues) and how the two types of GalAs are spatially distributed within that linear backbone. These distributions translate into an ordered vs. random distribution of ionic (demethylesterified) and neutral (methylesterified) regions. Enzymatic modification of pectin nanostructure is the only known method to introduce ionic blocks into pectin having a relatively high degree of methylesterification (> 20%). We have been characterizing the statistical parameters of average demethylesterified block size (1 – 4 nm) and number of demethylesterified blocks per molecule (0.1 – 2.0) following enzymatic or base demethylation of a model 94% DM homogalacturonan by excising demethylated blocks using limited endo polygalacturonase digestion. Additionally, for enzymatic demethylation we have modeled enzyme mode of action. We will report on results obtained by demethylation with several pectin methylesterase isozymes as well as by random chemical saponification. Additionally we will present results for rheological properties related to nanostructural modifications.
ISBN:978-1-4398-7138-6
Pages:852
Hardcopy:$199.95
 
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