5 ms·

> There exists a huge number of amino-acids, most of them are not made or used by the known living beings and of those made by living beings even fewer are used

> There exists a huge number of amino-acids, most of them are not made or used by the known living beings and of those made by living beings even fewer are used in proteins. Thanks for the clarification, I did not know this. "Roughly 500 amino acids have been identified in nature, but just 20 amino acids make up the proteins found in the human body." > but among them only about 10 of those used by living beings have been found, i.e. about one half of the amino-acids used in proteins. So you are in fact underscoring just how significant this finding is by Japan on just one out of more than "between 1.1 and 1.9 million asteroids larger than 1 kilometer (0.6 miles) in diameter" in the asteroid belt [2] [1] https://www.ajinomoto.com/aboutus/amino-acids/20-amino-acids https://www.ajinomoto.com/aboutus/amino-acids/20-amino-acids [2] https://solarsystem.nasa.gov/asteroids-comets-and-meteors/asteroids/in-depth/ https://solarsystem.nasa.gov/asteroids-comets-and-meteors/as...

adrian_b 4y ago
The returning of the asteroid sample and its analysis by Japan are very important and interesting. The problem is with the news report, which does not include the information that could have been interesting about the results. Instead of that, the news report stresses the number of amino-acids that happened to be found in the sample, which has an extremely low importance. Any extraterrestrial sample of matter which has condensed from a gas with the oxygen content under a certain threshold, and which has not been exposed to high temperatures that would vaporize the volatile organic substances is guaranteed to contain many amino-acids. Confirming the expectations is not newsworthy. If the news report would have contained the list of amino-acids, or better, also their proportions, that could have contained some useful information. A complete list might be too much in a news report for the general public, but there is some useful condensed information that could have been given instead of a complete list, i.e. how many proteinogenic amino-acids were among the 23, how many of the amino-acids were left-handed and how many right-handed, and whether there was any amino-acid which has not been found previously in matter of abiotic origin.
bigbillheck 4y ago
> "Roughly 500 amino acids have been identified in nature, but just 20 amino acids make up the proteins found in the human body." There are 20 used to assemble human proteins, but thanks to post-translational modifications there are lot more than that in the actual proteins.
- gilleain 4y ago
  There is also selenocysteine, which is cys with the sulfur replaced by selenium. https://en.wikipedia.org/wiki/Selenocysteine https://en.wikipedia.org/wiki/Selenocysteine It's not present in all organisms, but where it is, it is incorporated in proteins during translation, not after.

adrian_b 4y ago

The returning of the asteroid sample and its analysis by Japan are very important and interesting. The problem is with the news report, which does not include the information that could have been interesting about the results. Instead of that, the news report stresses the number of amino-acids that happened to be found in the sample, which has an extremely low importance. Any extraterrestrial sample of matter which has condensed from a gas with the oxygen content under a certain threshold, and which has not been exposed to high temperatures that would vaporize the volatile organic substances is guaranteed to contain many amino-acids. Confirming the expectations is not newsworthy. If the news report would have contained the list of amino-acids, or better, also their proportions, that could have contained some useful information. A complete list might be too much in a news report for the general public, but there is some useful condensed information that could have been given instead of a complete list, i.e. how many proteinogenic amino-acids were among the 23, how many of the amino-acids were left-handed and how many right-handed, and whether there was any amino-acid which has not been found previously in matter of abiotic origin.

bigbillheck 4y ago

> "Roughly 500 amino acids have been identified in nature, but just 20 amino acids make up the proteins found in the human body." There are 20 used to assemble human proteins, but thanks to post-translational modifications there are lot more than that in the actual proteins.

gilleain 4y ago
There is also selenocysteine, which is cys with the sulfur replaced by selenium. https://en.wikipedia.org/wiki/Selenocysteine https://en.wikipedia.org/wiki/Selenocysteine It's not present in all organisms, but where it is, it is incorporated in proteins during translation, not after.