KESaulcy Spring 2018

Kate Saulcy Chemistry Research 430

Spring 2018

Research Times

Thursday 1-5 PM

CHEM 430-01 = 0.25 credit = 4 hours per week.

Proposed Research Project

General Information

Advisor: Audra Sostarecz

Other research student collaborators:

Other Research Collaborators: Debbie Crans, Colorado State University

Proposed Project Description (PPD)

The polypeptide hormone, insulin, is known to aggregate into a hexamer in the presence of zinc ions. The Langmuir monolayer technique can be used to examine the transition between active monomeric insulin molecules and the hexameric form which is more difficult for the body to use. There are distinctive isotherm characteristics for both monomeric insulin and hexameric insulin. Zinc (II) chloride is added to the model membrane system to create hexamers of insulin. Conditions of the system are altered to learn about the dependence of insulin’s molecular conformation on factors such as pH and concentration. Chelating agents, such as (ethylenediaminetetraacetic acid) EDTA and citrate are added to effectively remove the zinc ion from the solution and observe the behavior of the insulin molecules. With the addition of EDTA to the monolayer of zinc exposed insulin, monomeric isotherm characteristics were noted, indicating the removal of zinc from the insulin hexamer and the creation of monomeric insulin. These molecular conformational changes affect the function of the insulin molecule in the human body.

Instruments to be used

Langmuir Monolayer Trough

References (2 minimum)

Aggregation of Insulin at the Interface. Li, Leblanc. J. Phys. Chem. B 2014, 118, 1181−1188. Sigma Aldrich Study of the Aggregation of Human Insulin Langmuir Monolayer. Liu, Johnson, Micic, et al. Langmuir 2012, 28, 3369−3377. Surface Chemistry and Spectroscopy of Human Insulin Langmuir Monolayer. Johnson, Liu, Thakur, et al. J. Phys. Chem. B 2012, 116, 10205−10212. Avanti Polar Lipids

Research pledge

I, Kate Saulcy, have read the Chem/Bioc 430 course syllabus and understand the general structure and expectations of the research program. The above material was prepared after consultation, and in conjunction with my research advisor.