How do high temperatures affect Rubisco's affinity for CO2?

High temperatures can negatively impact Rubisco's affinity for CO2 by decreasing its binding affinity. Rubisco, or ribulose-1,5-bisphosphate carboxylase/oxygenase, is a crucial enzyme in the photosynthetic process, facilitating the fixation of CO2 into organic molecules. Elevated temperatures can lead to a decrease in the enzyme's efficiency, which may result in altered enzyme conformation or increased rates of photorespiration, where Rubisco binds oxygen instead of CO2. This diminishes its ability to catalyze the carboxylation reaction effectively.

As temperatures rise, the kinetic stability and efficiency of Rubisco can be compromised, decreasing its capacity to bind CO2, which is essential for the plant's photosynthesis, and thus affecting overall plant productivity. The impact of temperature on enzymatic activity is a common phenomenon, and in the case of Rubisco, this temperature sensitivity can have significant implications for plant health and ecological dynamics in changing climates.