Correct phrase involving optical rotation of venom

[sbrothy]

TL;DR Summary

Can I write "l-isomer", "levo-isomer" or is the correct term "l-enantiomer" or "levo-enantiomer" or am I way off course here?

What it said in TL;DR:

I want to describe a situation where a laboratory technician synthesizes the wrong isomer(?) of a naturally occurring venom, ending up with the left hand molecule when aiming for the right hand one. However improbable that may sound to a bunch of pros like you.

It's for a detail in a short story where it occurs during, or after, autopsy as a smoking gun that the critter wasn't natural and the butler definitely didn't do it.

Perhaps this should be moved to the art or book advice forums come to think about it.

 

[DaveE]

As a chemistry layman (at least in this crowd) I'd simply leave it at l- or d-. You'll have to explain it in any case. More detailed jargon won't benefit most of your readers and will only insight nitpicking by the 0.00001% who are organic chemists. They won't complain about l- and d-, they'll know your abbreviating things.

Bottom line, make it read well. Jaws wasn't that accurate, but it made a lot of money for Benchley.

 

[Borek]

What @DaveE said.

In practice most more complicated molecules are not just L or D - morphine has five chiral centers (but as far as I am aware only on combination of configurations is biologically active). The exact description requires using five R/T designations in the name. These will be very confusing to anyone outside of chemistry.

Think about using word "racemate" - biological synthesis in vivo typically produces only one isomer, while synthesis in vitro often produces more of less 50:50 mixture of both L and D isomers. (That assuming one chiral center in the molecule). That's a known way of differentiating between natural and synthetic products.

Note that many venoms are actually polypeptides. While some aminoacids do have optical centers, typically only one form is present in living organisms, and common methods of synthesis use natural aminoacids and reproduce the structure exactly as it is, so the problem is mostly non-existent.

Interestingly, some reagents used in labs/in vitro are made from petroleum (not directly, but the petroleum is the main source of some compounds) which means they have a different isotopic composition than naturally occurring ones (think C14->C12). This can be used to prove something is synthetic (happened in sport doping cases).

 

[sbrothy]

EDIT: I actually deleted this post as I found it needlessly nerdy. Did a moderator un-delete it?

Moderators: I admit that this may be getting needlessly nerdy. This thread might increasingly belong in another subforum.


EDIT: Found the answer in the footnotes:

https://hal.science/hal-04016619/file/Manuscript+Fig+Suppl.pdf

Sorry.

Oh I can delete the post. Maybe it should stay as a warning about not using wiki for info. :)

Nah... I'll delete it in a sec..


I appreciate your responses and I'm now armed with enough info to get on. Just out of interest though... I read a little about venomous animals, specifically the black mamba about which wiki says: "Unlike many venomous snake species, black mamba venom does not contain protease enzymes.".).

So, when you say:

What @DaveE said.
[...] that many venoms are actually polypeptides. [...]

do you mean that the venoms themselves are polypeptides or that protease enzymes in, e.g. neurotoxins, break down proteins into them?

 

[Borek]

Enzymes (like proteases) ARE polypeptides (or proteins).

Not every polypeptide/protein is an enzyme, but all enzymes have at least polypeptide part (or are just polypeptides).

Note: I am using peptide/polypeptide/protein in a bit lousy manner. While splitting them into three categories can be sometimes convenient, technically they are all the same, mostly differing just by the size (peptides are the shortest, proteins are the longest, polypeptides are somewhere in between, all are just chains/polymers built of simple aminoacids).

 

[sbrothy]

Enzymes (like proteases) ARE polypeptides (or proteins).

Not every polypeptide/protein is an enzyme, but all enzymes have at least polypeptide part (or are just polypeptides).

Note: I am using peptide/polypeptide/protein in a bit lousy manner. While splitting them into three categories can be sometimes convenient, technically they are all the same, mostly differing just by the size (peptides are the shortest, proteins are the longest, polypeptides are somewhere in between, all are just chains/polymers built of simple aminoacids).

Thank you for your patience.

 

[sbrothy]

*BUMP*

Check top edit of my previous post.