Download effect of surfactant structure and properties on enzyme

EFFECT OF SURFACTANT STRUCTURE AND PROPERTIES
ON ENZYME-SURFACTANT INTERACATIONS
Derek Kim1 and P. Somasundaran1
Department of Earth & Environmental Engineering1, Columbia University; New York, NY 10027
Objectives: Develop compatible enzyme-surfactant systems
Challenges: Minimize enzyme function loss by modifying surfactant systems without sacrificing performance
Correlate structure and properties of surfactants with their interactions with enzymes to predict compatibility
Intellectual Motivation: Investigate impact of surfactant structure and properties on enzyme function (activity), structure (stability), and dynamics
Industrial Relevance: Home and Personal Care, Cosmetics, Foods, Pharmaceuticals, Renewable Energy, Biotechnology, Bioremediation
Broad Appeal: Enzyme-Surfactant Formulations, Enzyme Activity/Stability, Colloidal Interactions, Mixed Surfactants
Materials / Methods
Background / Problem
Enzymes: protease (positive charge), peroxidase (neutral charge)
• Enzymes increasingly used with surfactants in industries
Surfactants: anionic (SDS) / nonionic (AE, DM, APG)
Properties
• Enzyme activity lost in oppositely charged surfactants –
(aggregation,
micellization, charge)
of enzyme-surfactant
unfolding / denaturation occurs mainly due to:
colloidal systems surface tension, DLS,
 electrostatic repulsion of charges of bound
pyrene fluorescence
Structure and
dynamics of enzyme
surfactants
Enzyme activities with
with addition of
surfactants –
surfactants –Activity
assays with spectroscopy
stability/mobility –
 penetration of surfactant hydrocarbon chain into
S.S., time resolved
fluorescence
nonpolar regions of protein
Understand
mechanisms of
interactions
between
enzymes and
surfactants
•
•
•
Summary
1. Ionic surfactant – Enzyme activity suppressed by surfactant
monomers
2. Nonionic surfactant – Enzyme activity unchanged and even
enhanced at surfactant concentrations where loosely packed
micelles are formed → Disorder in water structure → Greater
enzyme flexibility → Higher activity
3. Mixed ionic-nonionic surfactant – Enzyme activity loss
lessened compared to single anionic surfactants
Hydrophobic interactions
Electrostatic interactions
Conformational change in
protein structure
Results
Protease Activity Change with Addition of
Anionic and Mixed Surfactants
Hypothesis
Interactions between an enzyme and mixed
surfactant system will be strongly dictated by
the ability of nonionic surfactant to form
mixed micelles with ionic surfactant and
inhibit electrostatic interactions
0
0
‐5
‐5
‐10
‐10
% Change in ‐15
Rate Constant
% Change in ‐15
Rate Constant
‐20
‐20
‐25
‐25
‐30
‐30
1 mM SDS
5 mM SDS
7.5 mM SDS
1 mM 1:1 SDS+AE
5 mM 1:1 SDS+AE
10 mM SDS
20 mM SDS
200 mM SDS
7.5 mM 1:1 SDS+AE
10 mM 1:1 SDS+AE
20 mM 1:1 SDS+AE
Future Plans
1. Investigate enzyme activity changes with various surfactant
systems
2. Investigate effects of surfactant properties on enzyme structure
and function and evaluate interaction mechanisms
3. Examine enzyme structural and dynamic changes with
addition of surfactants
Acknowledgement: This material is based upon work supported the National Science Foundation under Grant No. 1362060 and by CPaSS industry members.
Fall 2016 IAB Meeting – August 10-11, 2016