U.S. flagAn official website of the United States government
                    Here's how you know **Official websites use .gov**
                            
                            A **.gov** website belongs to an official government organization in the United States.
 **Secure .gov websites use HTTPS**
                            
                            A **lock** (                            
                              A locked padlock                                                      
                            
                            ) or **https://** means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.


Menu Agricultural Research Service
						
                    U.S. DEPARTMENT OF AGRICULTURE
 Bioenergy Research: Peoria, IL
 close



    Research

                    Research Projects
                                    Publications
                                    Collaborations
                                    News
                People

                    Staff Listing
                                    Careers


        


                    NCAUR Homepage
                    About BER
                        Mission Statement
                                    Strategic Goals
                                    Specialized Research ResourcesSearch small
                    Search
            
            ARS Home
                                About ARS
                                Contact Us




ARS Home Midwest Area Peoria, Illinois National Center for Agricultural Utilization Research Bioenergy Research Research Publications at this Location





- ARS National Programs
- Search for a scientific manuscript
- Search for a research project
- ARS Software
- Programs and Projects
- Collaborations
- Subjects of Investigation
- Publications

Title:   Author  item
                                            Mertens, Jeffreyitem
                                            Hector, Ronald

                                                         - *Ron*item
                                            Bowman, Michael
  Submitted to: Thermochimica Acta
                                    Publication Type: Peer Reviewed Journal
                                    Publication Acceptance Date: 10/27/2011
                                    Publication  Date: 11/2/2011
                                    Citation: Mertens, J.A., Hector, R.E., Bowman, M.J. 2012. Subsite binding energies of an exo-polygalacturonase using isothermal titration calorimetry. Thermochimica Acta. 527:219-222.Interpretive Summary: Meeting future fuel and specialty chemical needs will require the use of agricultural biomass. To be fully utilized, biomass needs to be broken down by chemical pre-treatments and enzymes into simple sugars. Rhizopus oryzae makes enzymes called polygalacturonases that are very effective in the conversion of pectin, a component of biomass, into simple sugars. Industrial interest in this enzyme is strong due to the use of this enzyme in clarifying fruit juices, textile production, and potential in the conversion of biomass to simple sugars. In this work we have determined the energetic properties of an exo-polygalacturonase binding to the complex sugars. This work aids in a greater understanding of how this enzyme works to break down more complex sugars and paves the way for development and engineering of more effective enzymes.
                                Technical Abstract: Thermodynamic parameters for binding of a series of galacturonic acid oligomers to an exo-polygalacturonase, RPG16 from Rhizopus oryzae, were determined by isothermal titration calorimetry. Binding of oligomers varying in chain length from two to five galacturonic acid residues is an exothermic process that is enthalpically driven and results in extremely tight binding of the substrate to RPG16. Binding energies in combination with prior biochemical data suggests that RPG16 has the potential for five subsites, -1 to +4, with the greatest contribution to binding energies arising from subsite -1/+1. While the enthalpic contribution to binding decreases substantially for subsites +2 to +4, beneficial entropic effects occur in subsites +3 and +4 leading to increased total free energy as the length of oligomer increases. This information will be useful for additional studies in determining the binding contributions of specific amino acids with mutant enzymes.


Return to top


Connect with ARS Sign up


ARS Home
                            USDA.gov
                            Plain Writing
                            Policies & Links
                            Civil Rights Statements
                            FOIA
                            Accessibility Statement
                            Privacy Policy
                            Non-Discrimination Statement
                            Quality of Information
                            USA.gov
                            WhiteHouse.gov