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> Generally speaking proteins can be found in meat

That isn't true at all.

And it only brings up the question: Where does the meat get the protein?

Animals can not make protein (or more accurately amino acids), only plants can. (Maybe some microorganisms too? Not sure.) Animals can only rearrange existing amino acids into other amino acids or into proteins.

All plants have protein, some more than others. Grains and legumes have the most of the plants.



> Animals can not make protein (amino acids actually), only plants can.

http://en.wikipedia.org/wiki/Amino_acid_synthesis

http://en.wikipedia.org/wiki/Essential_amino_acid


Yup, those links explain it in more detail.

But basically animals can only rearrange other amino acids, they can not be make them from basic elements.


https://en.wikipedia.org/wiki/Essential_amino_acid

Only 9 of the 22 "standard" amino acids can't be synthesized de novo by the human body.


That is simply untrue.

How exactly would you make an amino acid from glucose or a fatty acid? There is no nitrogen in either of those.

All those amino acids are made from OTHER amino acids.


Incorrect. Please read page 2 carefully.

http://www.tamu.edu/faculty/bmiles/lectures/biosynaa.pdf


> How exactly would you make an amino acid from glucose or a fatty acid?

With this: http://en.wikipedia.org/wiki/Citric_acid_cycle


Did you even read your own link?

The Critic acid cycle is awesome, but it can not perform nuclear synthesis. It has no way to making nitrogen.

As I've said 3 times already, it makes amino acids from other amino acids.

One of the ingredients is NAD, which is made from tryptophan or aspartic acid, both of which are amino acids.

You are simply wrong, and you need to update your information.

Animals can only make amino acids from other amino acids.


> One of the ingredients is NAD, which is made from tryptophan or aspartic acid, both of which are amino acids.

Or niacin: http://en.wikipedia.org/wiki/Niacin


You keep linking to pages that refute your own point.

NAD is made of nicotinamide AND Adenine. Adenine is in turn made from the amino acids glycine, glutamine, and aspartic acid.

Are you going to acknowledge you were wrong, and actually learn something? Or will you keep arguing?


That's what I get for not being explicit. You are utterly wrong. Take 10-15 minutes to read the linked pages and correct your metabolic fantasy.

Us animals are capable of amino acid synthesis for some amino acids.


No, it's you that is wrong. You clearly have not read the articles you yourself have linked.

> Us animals are capable of amino acid synthesis for some amino acids.

Really? You can make an amino acid from ammonia?

No, you can not. You can only make amino acids from other amino acids.

Here, I'll even link if for you: https://en.wikipedia.org/wiki/Amino_acid_synthesis#From_inte...

Follow each of the pathways there, and you will see. Each non-essential amino acid is made from another amino aid.


Do you realize that you went from animals not being able to synthesize proteins, to not being able to synthesize amino acids to not being able to get nitrogen from sources other than ingested amino acids?

Where will you move the post after you find out about niacin?


I quote my first message: "Animals can only rearrange existing amino acids into other amino acids or into proteins."

Nothing has changed in what I said since then.

> Where will you move the post after you find out about niacin?

As I replied elsewhere niacin alone is not enough.




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