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Polymorphism 2nd attempt?

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nen888

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..does anybody out there in advanced chemistry know what is required for a molecule to display polymorphism or different isometric forms? can this only be determined
by x-ray structural elucidation or something?

It's because of coming across different melting point materials that both seem 98%>pure DMT that i ask this..
 
..benzyme has answered the polymorphism question in my original posting (Open Discussions).

a friend told me australian flora has something like a 40% novel alkaloid rate in quick surveys. S.America must be similar.

so if any1 out there has ever done structural elucidation of molecules, be fantastic to have u onboard nexus.

thanks advanced chemists everywhere!
 
As a general rule, biologically produced molecules don't form stereoisomers because their synthesis relies upon specific binding positions to the enzymes that produce them. It's in synthetic chemistry where stereoisomers are produced when they're not wanted.

I'm only rather generally aware of those facts. There could be exceptions (but I would also say there might NOT be exceptions. Certainly there aren't exceptions with, say, amino acids).
 
Carvone and limonene are other examples, and there are several others.
If there's one thing I've learned from the field of biological chemistry it's that
There is a lot of hand-waving and supposed "rules" that always have exceptions.
In the case of tryptamines, it's a simple matter of the loss of the carboxyl, whether
En vivo or via synthesis, which eliminates the stereocenter.
 
According to wikipedia, both limonene and carvone are produced as only a single enantiomer in individual organisms (but different species produce different enantiomers, in the case of carvone).
 
benzyme said:
Claviceps spp. produces stereoisomers... Chanoclavine/iso-chanoclavine, lysergic acid, iso-lysergic acid, etc.
Click to expand...
I can't find a reference for that. There are some references that discuss chemical synthesis that STARTS with those biologic molecules, and then PRODUCES isomers.

As I said, I can hardly state that there are no exceptions; but exceptions are definitely not COMMON. I'd still like to see even one solid reference of a single organism actively creating more than one isomer in quantity (not talking about an occasional "mistake" ).
 
SWIMfriend said:
benzyme said:
Claviceps spp. produces stereoisomers... Chanoclavine/iso-chanoclavine, lysergic acid, iso-lysergic acid, etc.
Click to expand...
I can't find a reference for that. There are some references that discuss chemical synthesis that STARTS with those biologic molecules, and then PRODUCES isomers.

As I said, I can hardly state that there are no exceptions; but exceptions are definitely not COMMON. I'd still like to see even one solid reference of a single organism actively creating more than one isomer in quantity.
Click to expand...
Then you're not searching hard enough. Of course you won't find it in wikipedia

Handbook of Secondary Fungal Metabolites Vol. 1 Cole & Schweikert,
8-10,14,43-46.
 
Lol

I'm typing this from a blackberry. I got an electronic copy online from
Either rapidfiles or ebookee. It's THE reference. Make no mistake, these fungi
Produce a slew of stereoisomers, otherwise chrom wouldn't be so essential in separating
The alkaloids.
Paspalic acid and lysergic acid are two of the predominant
Isomers in c.paspali secondary metabolites
 
benzyme said:
Lol

I'm typing this from a blackberry. The electronic copy I got online from
Either rapidfiles or ebookee. It's THE reference. Make no mistake, these fungi
Produce a slew of stereoisomers, otherwise chrom wouldn't be so essential in separating
The alkaloids.
Click to expand...
Yes, I have no doubt a slew of stereoisomers are produced: a different one from each species! I'm interested in whether a SINGLE species (a single individual) ever produces more than one isomer. I have a feeling the answer is probably no. However, I have no experience with plant biology. My work was with vertebrates :)

Animals don't produce nearly the quantity and variety of "secondary metabolites" that plants do (in fact I don't really know of ANY in higher animals...)
 
I certainly don't mind being "wrong," since I originally said I wasn't sure about it by any means. I was curious, though, what the definitive answer was. It's interesting to know. Now I'd like to know more about the genes involved and how they evolved. It would be interesting to know considerably more about that case; for instance, was the evolution of the two isomers based on completely isolated/different evolutionary processes.

There's always the possibility that the molecules are quite large, and the enzyme doesn't bind to a key area, which is thus randomized for position, and so the isomers occur.
 
wow!..thank you, very educational...and it actually took me near a full minute to get the joke benzyme:)

if molecular structures cannot be completely predicted by theory (i.e no rules), especially not yet seen molecules,
am i right in assuming this shows a 'gap' of understanding between the fields of chemistry & physics? (or even mathematics & biology?)

any ideas out there..?
 
there exists a relatively new field of study which attempts to tie them all together, it's
called 'computational biophysics'. uses mathematical models to run simulations of conformational changes, protein subunit folding, etc.
here's a good site

in pharm r&d, 'de novo' drug design is the approach; it compares structural homologies based on pharmacophores. Tripos Muse is an example of a program which does this. it's actually used to invent new drugs.

if you'd like to visualize molecules, there are some incredible [free] visualization progs out there. Discovery Studio Visualizer, Pymol, VMD (from the biophysics site I listed above), Avogadro, and Marvin are all very good.
just download an sdf file from any chem you search on pubchem, and open it with any of those programs.
 
proteins are...."really"....better described as polymers rather than molecules (although, of course, "technically" they are molecules). Beyond well-categorized motifs, protein folding is unpredictable. Isomerizations of more "standard" molecules are VERY well understood, however. There is no mystery about the conformation of DMT in biologic systems.
 
benzyme said:
proteins are "technically" considered 'macromolecules'.
Click to expand...
Yes. DNA is a macromolecule, too...but it's put together by a "polymerase." It's useful to think of both DNA and proteins as "polymers" because they are the putting together of similar (rather than identical) subunits--into indeterminate length.
 
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