Amy Cohn

Publication Date


Document Type


First Advisor

Holbrook, Gabriel P.

Degree Name

B.S. (Bachelor of Science)

Legacy Department

Department of Biological Sciences


Rubisco is an enzyme that catalyzes the first reaction in the Calvin Cycle in photosynthesis. Since it is a poor catalyst, research has attempted to improve the rate at which it fixes carbon because this could in turn increase crop yields, in plants, Rubisco is regulated by light but the evolution of regulatory proteins and mechanisms is unknown. By studying Rubisco activity in photosynthetic bacteria, the origins of its regulation can be explored, we grew purple nonsulfur bacteria on two main substrates and used a culture grown in constant light conditions as a control. The experimental culture was grown in cyclic light and dark conditions to imitate the natural environment. Enzyme assays were performed on samples taken from both the experimental culture during both the light and dark parts of the cycle, we then analyzed the assay in terms of how much carbon was fixed per milligram of protein per hour, we found no evidence of inhibition of Rubisco in the dark. However, we conducted experiments in which we found a set of variables that gave optimal Rubisco activity.


Includes bibliographical references.


15 pages, 5 unnumbered pages




Northern Illinois University

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