Rubisco evolution

N. E. Tolbert4 has argued that the dual specificity of rubisco for C02 and 02 is not simply a leftover from evolution in a low-oxygen environment. He suggests that the relative activities of the carboxylase and oxygenase activities of rubisco actually have set, and now maintain, the ratio of C02 to 02 in the earth s atmosphere. Discuss the pros and cons of this hypothesis, in molecular terms and in global terms. How does the existence of C4 organisms bear on the hypothesis ... 

Rubisco and the Composition of the Atmosphere N. E. Tolbert has argued that the dual specificity of rubisco for C02 and 02 is not simply a leftover from evolution in a low-oxygen environment. 

Badger MR, Andrews TJ, Whitney SM, Ludwig M, Yellowlees DC, Lcggat W, Price GD (1998) The diversity and co-evolution of rubisco, plastids, pyrenoids and chloroplast-based COz concentrating mechanisms in algae. Can JBot 76 1052-1071... 

Reflect and Apply Rubisco has a very low turnover number, about 3COj per second. What might this low number tell us about the evolution of rubisco ... 

If rubisco was one of the first protein enzymes to arise early in the evolution of life, it may not have the efficiency of protein enzymes that evolved later, when evolution was more dependent on modifying and adapting existing proteins. 

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