Transaminase in Mammals: Science Watch Alert

[vampares]

OK. Transaminase in Mammals.

 

I am particularly concerned conversion of DL-methionine to L-methionine in mammals. Or any animal.

 

 

 

Primary Questions

1. Does "Transaminase" exist?
2. Does "Transaminase" convert DL-methionine to L-methionine?
3. Which "Transaminase" converts DL-methionine to L-methionine?
4. Is the aforementioned "Transaminase" encoded in the DNA of an animal?

 

Primary sub-questions will follow as needed.

[Moontanman]

Can you elaborate some on this?

 

 

OK. Transaminase in Mammals.

I am particularly concerned conversion of DL-methionine to L-methionine in mammals. Or any animal.

 

Why is this important?

[vampares]

Well, I could tell you, but, then I wouldn't get my straight answer. hahaha.

Can you elaborate some on this?

 

 

Why is this important?

 

DL-methionine is an ingredient in foodstuffs. Particularly foodstuffs for animals. Petfood is one example. Chicken feed is the second. I've seen in listed in horse supplements.

 

DL-methionine is not directly added to any food intended for human consumption, in the US, as far as I know. It may be *hidden*, per FDA regulation as an "artificial flavor". I think Hershey's Chocolate may contain DL-methionine and/or DL-phenylalinine.

 

D-amino acids are not ordinarily found in nature. D-methionine is definitely never found in the natural world.

 

D-methionine has somehow eluded the classification of a drug by being coupled with L-methionine. Please refer to the definition of "drug", foreign substance, harmful chemical and possible carcinogen.

Edited April 21, 2013 by vampares

[vampares]

I'll allow for any form of "transformation" that does not involve complete destruction of the base material. In other words, the metabolic pathway must be direct. Ammonium need not be involved.

 

 

The pathway may range from 100% success to 0% success. Branching of the pathway would be relevant. Anything goes, so long as it is concise.

 

 

Edit:

Scratch the first part. If the pathway involves destruction to base materials (rudimentary sulfur compounds specifically) this is acceptable as well.

Just as long as we have L-amino acids as an end result, or, rather no D-amino acids left.

Edited April 21, 2013 by vampares

[CharonY]

Both amino acids are found in nature, but only L-amino acids are found in proteins. Biosynthesis amino acid can lead to both forms. Transaminase are pretty much unrelated to this question, as they catalyze the exchange between amino and a keto group.

 

Think isomerase.

Edited April 23, 2013 by CharonY

[vampares]

Both amino acids are found in nature

 

Please. Where is the natural source of D-methioinine on earth? That I might find it...

 

 

as they catalyze the exchange between amino and a keto group.

 

 

SO, you know of apartic acid and α-keto. Aspartate aminotransferase. Of course.

 

 

 

Aspartate transaminase catalyzes the interconversion of aspartate and α-ketoglutarate to oxaloacetate and glutamate.   Aspartate (Asp) + α-ketoglutarate ↔ oxaloacetate + glutamate (Glu)

 

 

While Aminotransferase and Tarnsamionase are spelled completely differently, I love the prior art...I just can't make this sort of thing SHA-ZAM happen at will.

 

Notice >

It did say D -amino acid ... or does it? mmm nope.

is not the protein I need until I have D-methionine metabolized to α-ketoglutarate. (the fucking thing dosn't just start sucking up NH₃ like from anywhere... you know?...Where does the NH₃ go, how does it come back, why is this not reversible?

 

But you're right I am just sitting around, drinking a coke, looking for alot of free D-amino's to rearrange. I want to know how this process unfolds. Not just hypothetically or philosophically I could run into one of these in nature ...

 

free range, full scale, industrialized metabolism of D-methionine

 

Despotism 101: How does it go down?

[CharonY]

Now that got incoherent pretty quickly. But in case you wanted to know, bacteria actually produce D-amino acids (e.g. as elements during peptidoglycan synthesis). And as I said, there are enzymes responsible for the interconversion of the amino acid from the D to the L form.

[BabcockHall]

IIRC D-amino acid oxidase is one enzyme that degrades D-amino acids in mammals.

http://www.ncbi.nlm.nih.gov/pubmed/21956578

[vampares]

OK I just lost what I was going to post.

 

bacteria actually produce D-amino acids

 

Not exclusively or in racemic form. Is there one that produces D-methionine? Can the bacteria re-assimilate the D-methionine or is it a waste product?

 

D-amino acids may also have completely unrelated occurrences during metabolic processes. I do not have an example of one of these.

 

This whole d-amino bacteria thing sort an apocalyptic perspective. Like saying earthquakes build buildings. That's OK. I'm not sourcing DL-methionine from bacteria however, nor am I giving it to them.

 

There is some older research in which micro-organisms are cultured on a number of racemic amino acids (why? IDK. Ordinarily a little papain and some acid is all you would need). Racemic amino acids will not prevent the growth of micro-organisms. I have not found any documentation regarding what remained of the D-amino acids.

 

 

 

IIRC D-amino acid oxidase is one enzyme that degrades D-amino acids in mammals.

http://www.ncbi.nlm.nih.gov/pubmed/21956578

 

This is not a "transaminase". At least not yet. Methionine is slightly acidic, otherwise hydrophobic, so this may or may not work. The side-chain contains sulfur, so I'm not 100% sure we have this process complete yet. But this may just be all that is necessary to hurt the d-methionine.

 

DAAO or DAOX uses flavin adenine dinucleotide (FAD) co-factors.

 

 

 

Ordinarily l-methionine demethylates to l-homocystine with combines with l-serine and the sulfur is exchanged yielding l-cysteine and alpha-Ketobutyric acid (which is now achiral do to the loss of NH₃. Wikipedia is calling l-cysteine "semi-essential".

 

This is reliant upon Cystathionine beta-synthase. The enzyme has to hold on to some thing and it's either this D-amino group or the sulfur. Perhaps both.

 

Recognizing that the sulfur leaving homocysteine is chemically bonded, obviously the amino group has to be pulled off of it or stabilized in some way. The NH₃ is removed, along with a -H, and is replaced by the keto group. What is going to need to happen with the carboxylic acid is the question. Assuming the carboxylic acid remains intact it may form an ester -- and if so our enzyme is likely stereospecific.

 

The bird does think D-methionine can even yield the SAM-e, which is a perquisite. Sort of a strange hold on metabolic energy. Creepy.

Edited April 24, 2013 by vampares

[BabcockHall]

It is very difficult to figure out what question you are posing from what you just wrote. The chemistry by which methionine is converted into homocysteine refers solely to the L-isomer. I am not sure what you mean by a D-amino group.

Edited April 24, 2013 by BabcockHall

[vampares]

It is very difficult to figure out what question you are posing from what you just wrote. The chemistry by which methionine is converted into homocysteine refers solely to the L-isomer. I am not sure what you mean by a D-amino group.

 

It's about what the bird was saying. Are you sure I can't knock the methyl group off of there? This seemed to me to be where sulfur control would be the primary role in a fairly easy action as SAM-e is set up for ready usage.

 

Cobalamin is not stereospecific. Doesn't it carry a methyl group? Given the will to get one it could probably take it by shear will.

Edited April 24, 2013 by vampares

[Maximilian]

Methionine racemase