Changes in hydrogen bonding in protein plasticized with triethylene glycol

Abstract

Bloodmeal decolored with 4 wt % peracetic acid can be extruded into a semi-transparent bio-plastic through the addition of sodium dodecyl sulfate (SDS), water, and triethylene glycol (TEG). TEG is often used to plasticize protein thermoplastic materials because of its ability to form both hydrophobic and hydrogen bonds. Synchrotron-based FT-IR was used to monitor changes in the types of hydrogen bonding occurring in TEG plasticized protein during heating. Heating was found to overcome a portion of the weaker hydrogen bonds found within and between proteins, observed as a blue-shift in the N-H and O-H stretching vibrations occurring at 3280 cm 21 . TEG was shown to be involved in a larger array of hydrogen bonding environments after heating, evidenced by the broadening of the C-OH stretch around 1076 cm 21 , suggesting improved plasticizer-protein interactions. Additionally, these bonds were found to be as strong as the original interactions, observed as a shift in the C-OH peak back to its original wavenumber (1076 cm 21 ) during cooling. Initially, TEG was spatially distributed into distinct plasticizer-rich and plasticizer-poor domains, giving rise to two glass transitions. Heating allowed the migration and uniform dispersion of TEG throughout the material, and merged the two glass transitions into one broader glass transition region. Heating during DSC removed the peak around 60 C corresponding to the enthalpy of relaxation, which is associated with physical aging of amorphous and semi-crystalline polymers. While physical aging occurred during the storage of DBM, in the presence of TEG it occurred to a lesser extent. V C 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42166.

Substrate-Triggered Exosite Binding: Synergistic Dendrimer/Folic Acid Action for Achieving Specific, Tight-Binding to Folate Binding Protein

“…The interaction between polymer backbones and proteins is considered to be the most important factor in polymer-based drug delivery and biodevice development . Proteins have been shown to interact with polymers via a complex set of interactions that include generalized electrostatic, van der Waals, and H-bonding interactions and more specific protein–polymer binding . These interactions have generally been studied in the context of protein adsorption onto surfaces as opposed to the triggered exosite binding described herein.…”

A Study on the Combination of Enzyme Stabilizers and Low Temperatures in the Long-Term Storage of Glutamate Biosensor

“…A recent paper showed that TEG was able to provide long-lasting high levels of biosensor stability and sensitivity. In comparison with GLY, the larger size and greater conformational flexibility of TEG allowed the glycol to interact deeply with the enzyme proteins, activating hydrophilic and hydrophobic interactions with the amino acid residues located in a more internal portion of the protein [8,36,37].…”

A New Perspective on Using Glycols in Glutamate Biosensor Design: From Stabilizing Agents to a New Containment Net

“…The high number of active molecules and high sensitivity, as well as the constant enzyme affinity, reflect the elevated capability of TEG to stabilize enzymatic activity, over the time frame studied. Moreover, the persistence of many active enzyme molecules that were well-oriented for interaction with the substrate could be due to hydrophilic and hydrophobic interactions of TEG through OH moieties and ether oxygens [55,56]. Moreover, the structural flexibility of TEG probably allows better interactions with the amino acids of the enzyme.…”