How invariant is digestion of a certain substance?

[fresh_42]

TL;DR

How do enzymes change in an individual, say mammal?

In around 40% of people, $C_4H_6O_2S_2$ is enzymatically broken down into sulfur-containing compounds such as methanethiol, dimethyl sulfide, or dimethyl disulfide.

Is it basically possible to belong to these 40% and later in life to the other 60%? How stable is "enzymatically" and what are the mechanisms for a change? Where does the sulfur go?

 

[jim mcnamara]

Very short, very general answer - DNA is changed over time epigenetically - so the synthesis of an enzyme or some precursor molecule may affect the biological pathway. Or increase it. Or stop it. That is it. End of answer.

Unless you can tell me what your source has as actual chemical name of that molecule like maybe:
A. asparagusic acid or
2-ethanethioylsulfanylacetic acid
B. what you really want to know

That way I can look it up...

And yes aging affects lots of biochemical pathways.

And yes, there is a possibility of different mutations of one or more genes that build enzymes for the biochemical pathway which may speed up, slow down or even turn off the whole pathway at some point.
Or cause an alternate pathway to work overtime...

 

[fresh_42]

Thank you for the answer.

It is A, but I wanted an unbiased answer. I had in mind that it is genetically determined, so I was curious whether the genetic disposition can actually change. And as mentioned: where does the sulfur go unrecognized?

 

[jim mcnamara]

It can change over time and have a genetic basis . Sulfur goes into the compounds you listed. And ultimately ends up in your urine. Asparagus - the only known dietary source of asaparagusic acid - creates a funny "pee" smell in urine. Eat asparagus, and within 15 minutes the smell is in your urine.

White, R. H. (1975). "Occurrence of S-methyl thioesters in urines of humans after they have eaten asparagus". Science. 189 (4205): 810–811. Bibcode:1975Sci...189..810W. doi:10.1126/science.1162354. PMID 1162354.

And it is not unrecognized... AFAIK. An amino acid that has sulfur - cysteine - but it is not part of the biochemical pathways for asparagus residues. Kidneys and liver are the "garbage handlers", if there is a question about 'what to do with this molecule?' then these organs either store it in fatty tissues, or excrete it in urine.

 

[fresh_42]

And it is not unrecognized... AFAIK.

That phenomenon once was. Now it is gone and I wondered where to? And if sulfur still binds with oxygen and or hydrogen, then where does the smell end up? This question could be expanded to the digestion of onions. Where does the sulfur go? It's pretty obvious for garlic, but not so for onions, or as in my case, newly asparagus. I lost the logical explanation (= genetic disposition and smell) and seek for a new one.

 

[OCR]

I lost the logical explanation [. . .] and seek for a new one.

Where does the sulfur go?

.

 

[jim mcnamara]

I like @OCR ' approach best.

Sulfur is excreted in urine which I thought I said above. I guess not.

Biochemistry and sulfur levels in urine: pigs are a common animal model used as a proxy for humans when when you do not want to experiment on humans. There is also sulfur in feces, mostly as $H_2S$ due to gut microbiota activity. Kill of some them and you lose the distinctive fecal odor.

https://academic.oup.com/jn/article/133/3/766/4688065