Why Aspartame Isn't Scary

Just because it is a teachable moment certain molecules, like all amino acids with the exception of glycine, are chiral. Chiral means there is a "handedness" to them. The idea is that they are mirror-symmetric but not the same, like your hands. You get chirality in biochemical molecules whenever you have a carbon atom that is bonded to four different groups. That introduces what is known as a chiral center.

The handedness of the molecule refers to in what way the groups are arranged around that center.

https://www.thoughtco.com/amino-acid-chirality-4009939

The D- and L- refer to the orientation of those centers with D- standing for dextrose (or right handed) and L- standing for laevus (or left handed) and refer to the direction that light bends when shown on a solution of them (chiral molecules twist light).

The vast majority of naturally formed amino acids occur in the L- configuration. This is because the enzymes used in their anabolic construction happen to position the atoms in that way. As a result the D- configuration is not recognized by those enzymes and cannot be metabolized.

The chiral orientation of the carbon in the phenylalanine in aspartame is the same, its L-phenylalanine. There is a good reason for that as well, the dipepetide in aspartame is a natural product. Aspartame is just that aspartyl-phenylalanine dipeptide (which is 100% natural) methylated at the carboxal terminus of the phenylalanine residue forming the methyl ester.

This is the structure of aspartame:



Note that the chiral center for the phenylalanine residue is the carbon between the amino and carboxyl groups connected to the phenyl ring. Basically if the carboxyl and phenyl groups are in a plane the amino group is coming out of the page (black triangle)

Here is the structure of L-phenylalanine



Note that the connection to that carbon atom is the same with the amino group coming out of the page (the black triangle). Basically if the carboxl and phenyl groups are in a plane the amino group is sticking up.

In comparison here is D-phenylalalnine



Here in that orientation the carbon is the same but the amino group is receeding back into the page (the dashed lines). Basically if the carboxyl and phenyl groups are in a plane, the amino group is sticking down.

alicebhsia wrote: »

@Aaron_K123 i'm sorry but chemistry is definitely not my thing. idk, i guess you just won't be able to convince me that aspartame isn't scary. i do do the pink packet in my coffee though. the safety of saccharin in moderation has been endorsed by Edgar Cayce so it is safer in my eyes and i haven't had any negative effects so far. too bad he's not around anymore to chime in on aspartame. i don't trust Splenda though. it seems to give me immediate memory problems.

If chemistry isn't your thing then why did you make a claim about chemistry of aspartame by claiming that the chiral center of phenylalanine being different between proteins and aspartame? Do you feel comfortable positing statements for which you don't know what you are actually saying?

alicebhsia wrote: »

@Aaron_K123 i'm sorry but chemistry is definitely not my thing. idk, i guess you just won't be able to convince me that aspartame isn't scary. i do do the pink packet in my coffee though. the safety of saccharin in moderation has been endorsed by Edgar Cayce so it is safer in my eyes and i haven't had any negative effects so far. too bad he's not around anymore to chime in on aspartame. i don't trust Splenda though. it seems to give me immediate memory problems.

I am sorry to harp but this sort of thing is just very frustrating. When someone brings up chemistry as a reason for stating that aspartame might be of concern but then when I take a long time to respond with specifics about the chemistry that they themselves brought up I am not expecting the response back to be that they don't know anything about chemistry so chemistry isn't very convincing for them.

Then really why did you bring it up in the first place if its not something you know about or would be convinced by?

Is there a domain of this that you do fully understand that we could talk about?