Can your body synthesise protein from carbohydrates and nitrogen?

[wasteofo2]

If one had no way of eating any protein, but could eat carbohydrates and something which had nitrogen that wasn't a protein, could their body assemble proteins to use, or does that mechanism not exist?

[selfAdjoint]

Cows can do that, I believe, but not people. We have evolved to need some protein input.

[aychamo]

I don't know anything about the metabolism.

But I do know that some amino acids have sulfur groups in them so you would have to have some sulfur source.

[Monique]

Aychamo: amino acids have a NH3+ group, thus you need a nitrogen source (like wasteofo2 mentioned).

To answer his question: there are 10 essential amino acids that you need to get through your diet (arginine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, valine), the other 10 are non-essential: those can be biosynthesized in adequate amounts.

The essential amino acids are generally the ones with complex structures: aromatic rings and hydrocarbon side-chains. The non-essential ones are those readily synthesized from abundant metabolites, such as intermediates in glycolysis or the citric acid cycle.

Plant proteins are generally deficient in lysine, methionine, or tryptophan, so a vegetarian should eat a varied diet to compensate the deficiency in one source by an excess in another.

[aychamo]

Aychamo: amino acids have a NH3+ group, thus you need a nitrogen source (like wasteofo2 mentioned).


I know this. I said that some amino acids contain sulfur. That is Methionine and Cysteine. Eating only hydrocarbons and nitrogen wouldn't get you those :)

[Monique]

ahh, you had me there :wink: you're right :approve:

[aychamo]

I guess I should have said sulfur in their R-groups instead of saying they had sulfur groups. :)