In article <2ts7va$fdo at babyblue.cs.yale.edu>, johnk at loglady.ninds.nih.gov (John
Kuszewski) says:
>|>>>Both your proposals are complete crap. "Essential" amino acids are those
>that people can't synthesize for themselves, but plants can. We don't
>bother having synthetic mechanisms for all the AAs for the same reason
>that we don't bother having a synthetic mechanism for glucose (from CO2,
>that is)--it's perfectly easy just to eat plants, letting them do all
>the work.
>>>--
> _____________
> | ___/_
> | |/ /
> -- /\ // /--
> || || / /||
> || || / / ||
> || ||/ / ||
>John Kuszewski || |/ /| ||
>johnk at spasm.niddk.nih.gov || / /|| ||
> \/ / / || \/
>that's MISTER protein G to you! |/__/| |
> /_________|
Well...I am aware of the fact that we are unable to synthesize essential amino
acids...hence the name. But I think you missed the point. I am trying to
come up with an explanation for why we can synthesize *any* amino acids given
the fact that they occur in our diet at adequate levels (for the most part).
I argue that we have maintained these pathways because these amino acids play
some important regulatory role *besides* protein synthesis. For example
arginine biosynthesis in the urea cycle. I don't think we can lose this
biosynthetic pathway. What I am *most* interested in is people's opinion
on whether/not all essential amino acids must play some important role, and
that all non-essential ones have no role besides protein synthesis. Even
I think this may be too simplistic a view...but I can think of no examples
of essential amino acids having some important biological role.
Stephen Misener
Queen's U Biology
miseners at QUCDN.QueensU.CA
