"Yes, proteins have many mechanisms through which they "compete" or to be more specific, regulate one another in an inhibitory way"
Is this competition?
"Phosphorylation and methylation are the examples I know of."
I know that methylation has something to do with DNA, and changes the expression of genes. Phosphorylation means, kind of in the same way, that f.i. enzymes are turned on/active. I don't really see the competition there.
The coffee examples is a matter of choice, because you can either drink it or not (but franctly I don't have a choice anymore, it seems, because I drink coffee every morning, and I get a headache when I don't, but there is a personal choice involved. Just like smoking, which causes methylation, you can either smoke or not), but the flight-or-fight situation example shows that moment one type of molecules are extreted, and the other moment different molecules are. These molecules are not in competition with each other, are they/ And the sites that take up the molecules don't really have a choice, so I don't know if this is called 'competition'.
In fish (in this case salmon and trout) it seems to me (I read
here) that the females are even more active:
"We found that activating sperm in ovarian fluid makes them live about twice as long as in river water. Importantly, both species' sperm also switch from swimming in tight elliptical circles in river water, to swimming in straightened trajectories in ovarian fluid. This behaviour allows sperm to navigate towards the egg by following a chemical cue".
I'd like to know if proteins are, in the same way like the above examples, are considered 'in competition' which each other.