Post by Dr. HotSaltPost by Athel Cornish-BowdenPost by Dr. HotSaltPost by Athel Cornish-BowdenPost by Garrett WollmanPost by Jerry FriedmanI think it's more that the glutamate anion has the same kind of
biological function (amino acid) as a number of other molecules that
don't fit those receptors and that are not just edible but essential.
And those molecules are found together, being the components of
proteins. So a receptor that just happened to fit glutamate has the
adaptive value of helping us like protein-rich foods, which is why we
still have that receptor.
Well, famously, glycine is sweet (i.e., it binds the sweetness
receptor, hence the name), so I think your theory may explain too
much.
It is indeed true that glycine is sweet (it tastes much like sucrose)
but I'm not sure how famous that information is. Several times I've
asked classes of biochemistry students if anyone can tell me why it's
called glycine, and I've never found one who could. If biochemistry
students don't know how likely it is that members of the general
population know?
Apparently it was given that name *because* it tastes sweet.
Yes. It used to be commonplace for organic chemists to taste newly
isolated compounds.
I've heard some horror stories about that.
Post by Athel Cornish-BowdenThe psychodelic effects of LSD were discovered by
William Perkin Jr. after a crystal "accidentally" landed in his mouth.
I doubt whether it was really accidental -- he was too skilled a
chemist to have that sort of accident.
I thought that was Hoffman?
Could be. I was relying on my memory, and with Alzheimer coming on
that's not reliable.
Post by Dr. HotSaltPost by Athel Cornish-BowdenPost by Dr. HotSaltIt is an essential amino acid though,
It's not as simple as that. It used to be considered non-essential,
because it can be synthesized from serine, which is readily available.
By "essential" I meant Life As We Know It can't do without it.
In ordinary everyday language you're right, of course, but
nutritionists use "essential amino acid" in a technical sense to means
ones that must be in the diet because we can't make them ourselves.
Post by Dr. HotSaltPost by Athel Cornish-BowdenNowadays many nutritionists call it "conditionally essential." The
problem is that formation from serine is regulated by the demand for C1
units needed for anabolic metabolism, and not by the demand for
glycine. That works fine for small animals and growing animals, which
consume lots of C1 units, but not for large adult terrestrial animals,
which need a huge amount of glycine (collagen is the most abundant
protein in the human body, and one-third of it (by counting residues)
is glycine, or one-quarter (by mass)). Elderly people, as well as
elderly elephants and rhinoceroses in the wild, suffer from
osteoathritis and other collagen-related diseases.
Huh. Sounds like I needs me some then for my arthritis.
Unfortunately it's a long-term effect. You need to take it when you're
young. Having said that, I've been taking a few grams a day since about
2007. Before that I used to have pain in my feet when walking, and now
I mostly don't, so there may be some short-term value. I've also been
taking aspartic acid (NOT aspartate: you don't want all that sodium),
which does have a short-term effect and reduces the craving for
carbohydrates. Much nastier to eat than glycine, but you get used to
it. Both need to be food-grade, incidentally; chemical-grade products
may be 99.9% pure, but the 0.1% is stuff like arsenic that you don't
want to eat, and 0.1% in 5-10 g is not trivial.
Post by Dr. HotSaltYeah, I know, supplements don't really help.
Post by Athel Cornish-BowdenPost by Dr. HotSaltso that fits the "theory".
Not really. There is almost no free glycine in nature, and combined
glycine isn't sweet.
Just poking a little fun.
OK. I thought you probably were, but the pedant in me took charge.
Post by Dr. HotSaltPost by Athel Cornish-BowdenPost by Dr. HotSaltOn the other hand, so does lead [II] acetate.
Wealthy Romans used to store their wine in lead vessels, which leached
out the acetic acid (vinegar) and made the wine less sour and sweeter.
This must have had effects on their health and fertility.
I've read claims that they deliberately boiled the leftovers of
winemaking in lead pots to make the stuff which was then added to
certain wines to sweeten them.
There are historical cases of deliberate poisoning using it, and several
accidental cases.
Of course more than one person has wondered about the behaviors of some
notable Romans as possibly being due to the accidental effects.
Such as the tremendously high level of adoption of boys from poorer
families into richer ones for inheritance purposes.
I first heard about this 50 years ago from the wife of a colleague at
Berkeley. She did her PhD in ancient history; he has become a
distinguished scientist.
Surprisingly, he doesn't seem to have a wikiparticle, though his
daughter does. I remember when she was born. Everyone in the lab was
expecting babies at the same time in 1969. My then wife and I won the
race, and they came second.
--
athel