Dr. Rowlett will isolate and purify carbonic anhydrase, an enzyme thought to be important species such as corn. Once isolated in pure form, he will examine the structure of the enzyme and several laboratory-modified derivatives using UV-visible spectroscopy, and powerful X-ray absorption techniques. Dr. Rowlett also proposed to investigate the catalytic role of plant carbonic anhydrase in detail using nuclear magnetic resonance and stopped-flow spectroscopy methods which are capable of picking apart individual chemical steps in their mechanism of action. %%% Although carbonic anhydrases of animal origin are well-known, plant carbonic anhydrases are poorly understood, and what little is known indicates that the plant enzyme is evolutionarily distinct from carbonic anhydrases of animal origin. Thus, the characterization of plant carbonic anhydrases is highly significant, for two reasons. First, plant and animal carbonic anhydrase may represent one of a few pairs of enzymes in nature which have evolved from different origins to arrive at an identical function (convergent evolution). By comparing the structures of such convergently evolved enzymes, it will likely be possible to distinguish the essential and nonessential features of protein structure responsible for chemical catalysis. Second, the study of the catalytic ability of plant carbonic anhydrase may help resolve the exact function of plant carbonic anhydrase in photosynthesis, a function that is currently unknown, primarily because of a lack of fundamental information about the catalytic ability of the enzymes.
