Understanding the chemical perspectives of enzymes and their medical applications



Kohen Group

The Kohen Group, ca. spring 2017


Professor Amnon Kohen


B.Sc., Hebrew University in Jerusalem, Israel (1989)
D.Sc., Technion - Israel Institute of Technology (1994)
Postdoctoral Research Associate, University of California at Berkeley (1995-1999)

Dr. Amnon Kohen is a Professor of Chemistry and of Molecular and Cellular Biology. Amnon was born in a kibbutz in northern Israel. He served for six years in the Israeli navy. He received his B.Sc. degree in Chemistry in 1989 from the Hebrew University in Jerusalem and D.Sc. degree in 1994 from Technion-Israel Institute of Technology. After that he was a postdoctorial fellow with Prof. Judith Klinman at the University of California at Berkeley. In 1999, he moved to the University of Iowa. His main interest is bioorganic chemistry and he enjoys studying the mechanisms by which enzymes activate C-H bonds and N2 triple bonds. His research focuses on the relationship between enzyme structure, dynamics, and catalysis. He is also pursuing medical and technological applications of biological catalysts.


Assistant Research Scientist


Priyanka Singh

Phone: 319-335-0334
Email: priyankanarendra-singh@uiowa.edu
Office: E 276 CB (Chemistry Building)

Priyanka was born in Nasik (India). She received her BSc and MSc in microbiology from University of Pune (India). After her masters, she went to the Institute of Neuroscience and Biophysics at Forschungszentrum Jülich, Germany for a short-term research project. She received her PhD in 2015 from the University of Iowa (USA) under the supervision of Professor Amnon Kohen. During her PhD studies, she worked on the nature and extent of enzyme dynamics and protein motions in dihydrofolate reductase, both by using traditional experimental methods and by developing new biophysical probes of protein dynamics in this system. She is currently a research scientist and continues to work in the Kohen research group. Her research interests lie in understanding the molecular basis of enzyme evolution.


Graduate Students


crChethya Upalakshi

I am from Sri Lanka and I obtained my B.Sc. Special degree in Chemistry from the University of Sri Jayewardenepura, Sri Lanka in year 2011. I like to pursue interdisciplinary studies in Chemistry and after coming to the University of Iowa I got very much interested in Kohen’s group.


NickLuedtke2017Nicholas Luedtke

Graduate Teaching Assistant 
University of Iowa Chemistry Department
Office: E 262 CB (Chemistry Building)

Nicholas was born and raised in Appleton, Wisconsin. He completed his bachelor’s degree in chemistry at Ripon College, Ripon, WI in 2016. He came to the University of Iowa in 2017 interested in biochemistry and protein crystallography, but engaged himself in elucidating enzyme catalytic mechanisms, specifically flavin-dependent thymidylate synthase. Outside of the laboratory, Nicholas spends his free time running competitively, cycling, snowboarding, and cooking.  


Jiayue Li

Email: jiayue-li@uiowa.edu
Office: E 276 CB (Chemistry Building)

I am from the northeastern part of China. I received my bachelor degree in East China University of Science and Technology, Shanghai, China in 2013. Then I went to study in Hong Kong Baptist University and obtained my M.Sc. degree in Analytical Chemistry. In the fall of 2014, I joined Prof. Kohen’s group and start my Ph.D. studies on the project of DHFR. I enjoy listening to music and watching TV series during my free time.


johnJohn Terrel


University of Iowa Chemistry Department

Office: E 276 CB

Email: john-terrel@uiowa.edu


John was born in Kanab, Utah about twenty minutes away from Zion National Park. He completed his bachelor's degree in chemistry in 2016 at Southern Utah University in Cedar City, Utah. He came to the University of Iowa in Fall of 2016 interested in physical chemistry and joined the Kohen/Cheatum collaboration studying enzyme dynamics in DHFR. Outside of the lab he enjoys being outdoors and spending time with friends and family. 


laurenLauren Lambach

University of Iowa Chemistry Department

Office: E 276 CB

Email: lauren-lambach@uiowa.edu

Lauren is from Big Bend, Wisconsin.  She graduated from Bradley University in 2017 with bachelor’s degrees in biochemistry and mathematics.  She came to the Univeristy of Iowa in the fall of 2017 interested in biochemistry, physical chemistry, and enzymology.  Outside of the lab, she enjoys competing in triathlons and spending time with family and friends


Undergraduate Students


Gabriel Antonio Fortunato

I am a Biochemistry major with hopes of studying medicine someday. I joined Kohen Research Group in 2015, and have been working with Priyanka on her studies of DHFR. I also love sports, traveling, learning new things, and trying new foods. I am an avid supporter of a Brazilian soccer team called Grêmio.



Lab Alumni           Past Pictures


Phil Pagano

Graduate Research Assistant 
University of Iowa Chemistry Department
Phone: 630-649-4105
Office: E 262 CB (Chemistry Building)

I did my undergraduate at Northern Illinois University in Dekalb where I developed a serious interest in chemistry and biochemistry.  I originally  came to Iowa to study biochemistry, however became very interested in techniques and methods of physical chemistry once I came to this department.  I then decided to work as a joint student with Amnon Kohen and Christopher Cheatum.  My research studies will focus on using advanced spectroscopic techniques (two dimensional infrared spectroscopy) developed Prof. Cheatum's lab to measure dynamic environments in enzymes such as Dihydrofolate Reductase which has been extensively studied by use of kinetic isotope effects in Prof. Kohen's lab.  Outside of the lab I spend my time listening to and playing music, watching Iowa and Chicago sports, and cooking.  I also enjoy traveling when I can find the time to do so.