# What does “dep” mean?

I'm looking at some data with substrate concentration on the $x$-axis and $k_\text{dep}$ on the $y$ axis. What does $k_\text{dep}$ mean? I understand that it must be a rate of some kind but what is the significance of the 'dep' part?

The data I'm looking at can be found in Fig. 9 in this paper (PDF): Essentially this is a dose response curve for a substrate and enzyme. I suspect $k_\text{dep}$ is simply the rate but why $k_\text{dep}$ and not just $k$?

• Material deposition on a surface? I'm just guessing too! – Klaus-Dieter Warzecha Apr 9 '15 at 11:13
• I looked at the paper. It uses a lowercase k with a subscript "dep" for the symbol you are asking about. You can use those symbols in your questions -- see here for more info. This time, I'll edit your question to give you an example of how to do this. – Curt F. Apr 9 '15 at 14:29
• The "dep" probably stands for "depletion": read the paper you linked to for more context. Often times, subscripts on rate constants are used to refer to which reaction in a system of multiple reactions. You'll see $k_1$ and $k_2$ for rate constants of "reaction 1" and "reaction 2", etc. – Curt F. Apr 9 '15 at 14:32

The "dep" probably stands for "depletion": read the paper you linked to for more context. Often times, subscripts on rate constants are used to refer to which reaction in a system of multiple reactions. You'll see $k_1$ and $k_2$ for rate constants of "reaction 1" and "reaction 2", etc.
I suspect in the paper, they were measuring the depletion of a substrate, and not what the substrate was converted to. So they wouldn't know if they were measuring the rate of a single reaction $\ce{A->B}$, or the combined rates of multiple reactions such as $\ce{A->B}$ and $\ce{A->C}$. Thus (probably) the desire to indicate $k_{depletion}$ instead of just $k$.