  By considering the energy cost of messages carried by proteins as
proportional to their information content we found experimental proof that
proteins from all living organisms tend to have their estimated semantic
content of information per unit mass, statistically, close to a constant. Thus,
in the message carried by proteins -to achieve minimum energy waste- the rate
of information content per unit mass tends to be optimized in living organisms.
The experimental evidence of this new information law resembles a marathon
where highly optimized proteins correspond to advanced runners followed by a
main bunch and the stragglers -lowly optimized proteins. Our results suggest
the existence of a continuous optimization process that living organisms had to
face, in which a compromise between biological functionality, economic
feasibility and the survival requirements is established.
