Question

When looking at this paragraph in Midorikawa's work for a fluorescence review I was confused, specifically around a time constant of ~4s being compared to ~300 ms.

1. It is not explicitly mentioned so I assume the 300 ms is a time constant correct?
2. How is the conclusion drawn that it is the step after tethering, priming, by the discrepancies in time constant? I am not hoping any readers know why biologically it is this way but rather how I can understand a 13x larger time constant can lead to conclusions that it is not rate-limiting? (emphasis mine)

Answer 1

The student is asking about the time constants in Midorikawa's work on fluorescence review and the conclusion drawn based on the discrepancies in time constants.

Step-by-step explanation:

In this paragraph from Midorikawa's work on fluorescence review, the student is confused about the time constant of ~4s compared to ~300 ms.

1. Time Constant:

Based on the given information, the assumption that the 300 ms is a time constant is correct. A time constant represents the time it takes for a system to reach a particular state or equilibrium. In this case, the time constant of ~4s and ~300 ms refer to different processes or steps in the reaction being studied.

2. Conclusion about Rate-Limiting Step:

The conclusion about the step after tethering, priming, is drawn based on the discrepancies in the time constants. A larger time constant indicates a slower process or step. Therefore, when there is a 13x larger time constant for a particular step compared to another step, it suggests that the slower step is not rate-limiting. In other words, the slower step does not significantly affect the overall rate of the reaction.